fix: task 10 + review fix #1 — thread safety and sleep bug

Fix #1: Don't sleep after the final exhausted retry attempt in
_graph_request(). The sleep on the last iteration was pure overhead —
the loop exits immediately after, so the caller just waited an extra
backoff period for no reason. Guard with attempt < _MAX_RETRIES - 1.

Task 10: Add threading.Lock (_edits_lock) for all compound operations
on active_edits, which is accessed from both the UI thread and
background edit threads:
- __init__: declare self._edits_lock = threading.Lock()
- open_file: snapshot already_editing and at_limit under the lock,
  then release before showing blocking UI dialogs
- process_file: wrap initial dict assignment, waiting=True, the
  in-check+waiting=False, and in-check+del under the lock
- on_done_editing_clicked: lock the items() snapshot used to build
  waiting_files, preventing iteration over a dict being mutated

Add 8 new unit tests (1 for Fix #1 sleep count, 7 for Task 10 lock).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitignore

@@ -45,3 +45,7 @@ searchindex.json
 
 # Temporary files
 C:\Temp_SP\
+
+# Project tooling / AI assistant files
+tasks/
+.claude/

README.md

@@ -6,13 +6,27 @@ En moderne Python-baseret fil-browser til Microsoft SharePoint, specielt designe
 
 - **Ingen Sti-begrænsning (MAX_PATH):** Problemfri og pålidelig redigering uanset mappedybde i SharePoint.
 - **Sikker Redigering & Kollision-beskyttelse:** Automatisk Check-out/Check-in og intelligent overvågning af fil-låse lokalt.
-- **Professionel Brugerflade:** Bygget med `wxPython` (Native Windows UI) inklusiv indfødte OS-ikoner, brødkrummesti (breadcrumbs) og lazy-loading af hierarkisk træstruktur for markant hurtigere navigation.
+- **Professionel Brugerflade:** Bygget med `wxPython` (Native Windows UI) inklusiv indfødte OS-ikoner, data-drevet brødkrummesti (breadcrumbs) og lazy-loading af hierarkisk træstruktur for markant hurtigere navigation.
+- **Paginering & Stor-tenant understøttelse:** Alle Graph API-kald følger `@odata.nextLink` automatisk, så mapper og sites med hundredvis af elementer indlæses korrekt uden tab.
+- **Statuslinje med fremgangsmåler:** En integreret statusmåler (gauge) i statuslinjen giver visuelt feedback under alle netværksoperationer.
 - **First-Run Setup Wizard:** Automatisk konfigurationsguide ved første opstart, der opsamler Client ID og Tenant ID (kræver ingen forudgående manuel `settings.json`).
 - **Avanceret Søgning:** Hurtig global søgefunktion der bygger på et lokalt, trinvist opdateret indeks, samt understøttelse af "OG"-logik (AND logic).
 - **Fuld Fil- og Mappestyring:** Understøtter upload, sletning og omdøbning, samt visning af udvidet fil-metadata (filstørrelse, redigeringsdato).
 - **Multisprog:** Indbygget og brugerstyret understøttelse af både Dansk og Engelsk-grænseflade.
 - **Multi-File Editing:** Robust understøttelse for lokalt at redigere flere forskellige filer uafhængigt af hinanden i baggrunden uden at interface fryser.
 
+## ⚙️ Indstillinger
+
+Indstillingsdialogen er organiseret i faner:
+
+| Fane | Indhold |
+|------|---------|
+| **Konto** | Azure Client ID og Tenant ID |
+| **Stier** | Midlertidig downloadmappe og app-placering |
+| **Licens** | Licensnøgle og aktiveringsstatus |
+| **System** | Sprog og log-output til fejlfinding |
+| **Om** | Versionsinformation og kontaktoplysninger |
+
 ## 🛠️ Teknologier
 
 - **Sprog:** Python 3.x
@@ -31,7 +45,7 @@ pip install wxPython msal requests
 ```
 
 ### Kør applikationen
-Star op med:
+Start op med:
 ```bash
 python sharepoint_browser.py
 ```
@@ -39,21 +53,34 @@ python sharepoint_browser.py
 Ved første kørsel uden en konfiguration vil applikationen præsentere en Setup Wizard, hvor man nemt kan indtaste Microsoft-loginoplysningerne. Indtastningerne gemmes i en lokal `settings.json` fil.
 
 ## 🏗️ Byg til EXE (Valgfrit)
-For at pakke programmet til en uafhængig, "kør-bar" `.exe` fil til Windows, kan dette gøres med PyInstaller:
+For at pakke programmet til en uafhængig, kørbar `.exe` fil til Windows bruges den medfølgende PyInstaller spec-fil:
+
 ```bash
 pip install pyinstaller
-python -m PyInstaller --windowed --onefile --icon=icon.ico --name "SharePoint Browser" sharepoint_browser.py
+python -m PyInstaller "SharePoint Explorer.spec" --noconfirm
 ```
-*(Husk at afhæningheder og ikoner skal inddrages formelt i dit build afhængigt af din PyInstaller spec-fil).*
+
+Den færdige fil placeres i `dist/SharePoint Explorer.exe` med ikon indlejret.
 
 ## 🧩 Arkitektur & Workflow
-1. **Godkendelse:** Det autentificerer brugeren via MSAL & MS Graph API.
-2. **Navigation:** Data hentes asynkront (lazy-loading). Alt håndteres med ID'er istedet for filstier, hvilket sikrer MAX_PATH-modstandsdygtighed.
-3. **Baggrundshåndtering af redigering:**
+1. **Godkendelse:** Autentificerer brugeren via MSAL & MS Graph API.
+2. **Navigation:** Data hentes asynkront (lazy-loading) og chunked — de første resultater vises straks mens resten streames ind. Alt håndteres med ID'er i stedet for filstier, hvilket sikrer MAX_PATH-modstandsdygtighed.
+3. **Navigationskontekst:** Brødkrummestien er data-drevet; hvert segment gemmer det fulde navigationsobjekt, så klik på en forælder altid navigerer korrekt uden at gennemsøge træet.
+4. **Stale-result beskyttelse:** En navigations-tæller (`_nav_gen`) sikrer, at svar fra afbrudte netværkskald aldrig overskriver den aktive mappevisning.
+5. **Baggrundshåndtering af redigering:**
     - Filer tjekkes ud (`Checkout`) direkte i SharePoint.
-    - Hentes ned til det lokale drev under korte stier under C-drevet eks. `C:\Temp_SP\[MD5-Hash].[ext]`.
-    - Et baggrunds-thread overvåger derefter det lokale program (fx Word) kontinuerligt via `os.rename()` tricket.
-    - Når filen lukkes fra dit office-program, uploades ændringerne op til SharePoint og modtager et `Checkin`.
+    - Hentes ned til det lokale drev under korte stier, eks. `C:\Temp_SP\[MD5-Hash].[ext]`.
+    - Et baggrunds-thread overvåger det lokale program (fx Word) kontinuerligt via `os.rename()` tricket.
+    - Når filen lukkes, uploades ændringerne til SharePoint og modtager et `Checkin`.
+
+## 🧪 Tests
+En unit-test suite dækker de kritiske logik-komponenter:
+
+```bash
+python -m unittest tests.test_review_fixes -v
+```
+
+Testene kører uden skærm/display og dækker: navigations-tæller, oversættelses-nøgler, URL-initialisering og signaturer.
 
 ## 💡 Backlog / Kommende muligheder
 1. Integration for håndtering af flere tenants (lejemål)

sharepoint_browser.py

@@ -67,13 +67,36 @@ def load_settings():
     with open(SETTINGS_FILE, 'r', encoding='utf-8') as f:
         try:
             return json.load(f)
-        except:
+        except Exception:
             return default_settings
 
 def save_settings(new_settings):
     with open(SETTINGS_FILE, 'w', encoding='utf-8') as f:
         json.dump(new_settings, f, indent=4)
 
+# --- GRAPH API REQUEST HELPER ---
+_RETRY_STATUSES = {429, 503}
+_MAX_RETRIES = 3
+
+def _graph_request(method, url, **kwargs):
+    """Thin wrapper around requests.request with retry for 429/503.
+
+    Retries up to _MAX_RETRIES times when Graph API signals rate limiting
+    (429) or transient unavailability (503), honouring the Retry-After header
+    when present.  A default timeout of 30 s is injected if the caller does
+    not supply one.  File-upload calls that pass an open stream as data=
+    should use requests.put() directly, since a stream cannot be re-read.
+    """
+    kwargs.setdefault("timeout", 30)
+    for attempt in range(_MAX_RETRIES):
+        res = requests.request(method, url, **kwargs)
+        if res.status_code not in _RETRY_STATUSES:
+            return res
+        if attempt < _MAX_RETRIES - 1:  # Don't sleep after the final attempt
+            retry_after = int(res.headers.get("Retry-After", 2 ** attempt))
+            time.sleep(min(retry_after, 60))
+    return res  # Return last response after exhausting retries
+
 settings = load_settings()
 CLIENT_ID = settings.get("client_id")
 TENANT_ID = settings.get("tenant_id")
@@ -179,6 +202,7 @@ STRINGS = {
         "settings_license_status": "Status: Ikke aktiveret",
         "settings_logging_group": "System / Diverse",
         "settings_logging": "Aktiver log-output (anbefales til fejlfinding)",
+        "status_loading_items": "Henter... ({count} emner)",
         "settings_about_group": "Om programmet",
         "settings_credits": "© 2026 SharePoint Explorer\n\nSkabt af:\nMartin Tranberg\nBlueprint\n\nBernhard Bangs Allé 23, 2.\n2000 Frederiksberg\n\nTel: 70258689"
     },
@@ -275,6 +299,7 @@ STRINGS = {
         "settings_license_status": "Status: Not activated",
         "settings_logging_group": "System / Miscellaneous",
         "settings_logging": "Enable log output (recommended for troubleshooting)",
+        "status_loading_items": "Loading... ({count} items)",
         "settings_about_group": "About",
         "settings_credits": "© 2026 SharePoint Explorer\n\nCreated by:\nMartin Tranberg\nBlueprint\n\nBernhard Bangs Allé 23, 2.\nDK-2000 Frederiksberg\n\nPhone: +45 70258689"
     }
@@ -498,7 +523,7 @@ class SettingsDialog(wx.Dialog):
         
         sys_vbox.Add(sys_inner, 1, wx.EXPAND | wx.ALL, 15)
         sys_panel.SetSizer(sys_vbox)
-        self.nb.AddPage(sys_panel, "System")
+        self.nb.AddPage(sys_panel, self.get_txt("settings_logging_group").split("/")[0].strip())
         
         # 5. ABOUT TAB
         about_panel = wx.Panel(self.nb)
@@ -669,9 +694,11 @@ class SharePointApp(wx.Frame):
         self.current_items = [] # Gemmer graf-objekterne for rækkerne
         self.tree_item_data = {} # Mappenoder -> {type, id, name, drive_id, path}
         self.current_path_data = [] # Gemmer data-objekterne for den nuværende sti (brødkrummer)
+        self._nav_gen = 0  # Incremented on each navigation to discard stale fetch results
         self.tree_root = None
         self.is_navigating_back = False
         self.active_edits = {} # item_id -> { "name": name, "event": Event, "waiting": bool }
+        self._edits_lock = threading.Lock()
         self.favorites = settings.get("favorites", [])
         self.fav_visible = settings.get("fav_visible", True)
         self.sort_col = 0 # Default (Navn)
@@ -705,7 +732,7 @@ class SharePointApp(wx.Frame):
             try:
                 self.msal_app = msal.PublicClientApplication(CLIENT_ID, authority=AUTHORITY)
             except Exception as e:
-                print(f"MSAL Init Error: {e}")
+                logger.error(f"MSAL Init Error: {e}")
         
         self.InitUI()
         self.Centre()
@@ -734,7 +761,7 @@ class SharePointApp(wx.Frame):
         if kwargs:
             try:
                 return text.format(**kwargs)
-            except:
+            except Exception:
                 pass
         return text
 
@@ -928,7 +955,6 @@ class SharePointApp(wx.Frame):
         # Add a Gauge to the status bar
         self.gauge = wx.Gauge(self.status_bar, range=100, size=(140, 18), style=wx.GA_HORIZONTAL | wx.GA_SMOOTH)
         self.gauge.Hide()
-        self.Bind(wx.EVT_SIZE, self.on_status_bar_resize)
 
         panel.SetSizer(vbox)
         self.Bind(wx.EVT_SIZE, self.on_resize)
@@ -1168,7 +1194,7 @@ class SharePointApp(wx.Frame):
             status_text = "Sletter" if self.lang == "da" else "Deleting"
             self.set_status(f"{status_text} {count+1}/{total}: '{item['name']}'...")
             url = f"https://graph.microsoft.com/v1.0/drives/{item['drive_id']}/items/{item['id']}"
-            res = requests.delete(url, headers=self.headers)
+            res = _graph_request("DELETE", url, headers=self.headers, timeout=30)
             if res.status_code in [204, 200]:
                 count += 1
             else:
@@ -1195,7 +1221,7 @@ class SharePointApp(wx.Frame):
         url = f"https://graph.microsoft.com/v1.0/drives/{drive_id}/items/{parent_id}:/{filename}:/content"
         try:
             with open(local_path, 'rb') as f:
-                res = requests.put(url, headers=self.headers, data=f)
+                res = requests.put(url, headers=self.headers, data=f, timeout=120)
             if res.status_code in [200, 201]:
                 self.set_status(self.get_txt("msg_upload_success", name=filename))
                 self._refresh_current_view()
@@ -1236,7 +1262,7 @@ class SharePointApp(wx.Frame):
     def _create_folder_sync(self, name, drive_id, parent_id):
         url = f"https://graph.microsoft.com/v1.0/drives/{drive_id}/items/{parent_id}/children"
         body = {"name": name, "folder": {}, "@microsoft.graph.conflictBehavior": "rename"}
-        res = requests.post(url, headers=self.headers, json=body)
+        res = _graph_request("POST", url, headers=self.headers, json=body, timeout=30)
         if res.status_code in [200, 201]:
             return res.json().get('id')
         return None
@@ -1246,7 +1272,7 @@ class SharePointApp(wx.Frame):
         filename = os.path.basename(local_path)
         url = f"https://graph.microsoft.com/v1.0/drives/{drive_id}/items/{parent_id}:/{filename}:/content"
         with open(local_path, 'rb') as f:
-            requests.put(url, headers=self.headers, data=f)
+            requests.put(url, headers=self.headers, data=f, timeout=120)
 
     def on_new_folder_clicked(self, event):
         if not self.current_drive_id: return
@@ -1280,7 +1306,7 @@ class SharePointApp(wx.Frame):
         self.set_status(f"{self.get_txt('msg_rename')}...")
         url = f"https://graph.microsoft.com/v1.0/drives/{item['drive_id']}/items/{item['id']}"
         body = {"name": new_name}
-        res = requests.patch(url, headers=self.headers, json=body)
+        res = _graph_request("PATCH", url, headers=self.headers, json=body, timeout=30)
         if res.status_code in [200, 201]:
             self.set_status(self.get_txt("msg_success"))
             self._refresh_current_view()
@@ -1301,7 +1327,7 @@ class SharePointApp(wx.Frame):
             with wx.DirDialog(self, self.get_txt("msg_select_folder"), style=wx.DD_DEFAULT_STYLE | wx.DD_DIR_MUST_EXIST) as dd:
                 if dd.ShowModal() == wx.ID_OK:
                     parent_path = dd.GetPath()
-                    dest_path = os.path.join(parent_path, item['name'])
+                    dest_path = os.path.join(parent_path, os.path.basename(item['name']))
                     threading.Thread(target=self._download_folder_bg_task, args=(item, dest_path), daemon=True).start()
 
     def _download_file_bg_task(self, item, dest_path):
@@ -1317,7 +1343,7 @@ class SharePointApp(wx.Frame):
 
     def _download_file_sync_call(self, drive_id, item_id, dest_path):
         url = f"https://graph.microsoft.com/v1.0/drives/{drive_id}/items/{item_id}/content"
-        res = requests.get(url, headers=self.headers)
+        res = _graph_request("GET", url, headers=self.headers, timeout=30)
         if res.status_code == 200:
             with open(dest_path, 'wb') as f:
                 f.write(res.content)
@@ -1336,12 +1362,12 @@ class SharePointApp(wx.Frame):
             
         url = f"https://graph.microsoft.com/v1.0/drives/{drive_id}/items/{folder_id}/children"
         while url:
-            res = requests.get(url, headers=self.headers)
+            res = _graph_request("GET", url, headers=self.headers, timeout=30)
             if res.status_code == 200:
                 res_data = res.json()
                 items = res_data.get('value', [])
                 for item in items:
-                    item_path = os.path.join(local_dir, item['name'])
+                    item_path = os.path.join(local_dir, os.path.basename(item['name']))
                     if 'folder' in item:
                         self._download_folder_recursive_sync(drive_id, item['id'], item_path)
                     else:
@@ -1359,6 +1385,9 @@ class SharePointApp(wx.Frame):
             if start:
                 self.gauge.Show()
                 self.gauge.Pulse()
+                rect = self.status_bar.GetFieldRect(1)
+                self.gauge.SetPosition((rect.x + 5, rect.y + 2))
+                self.gauge.SetSize((rect.width - 10, rect.height - 4))
             else:
                 self.gauge.Hide()
                 self.gauge.SetValue(0)
@@ -1377,6 +1406,7 @@ class SharePointApp(wx.Frame):
         wx.CallAfter(_do)
 
     def on_done_editing_clicked(self, event):
+        with self._edits_lock:
             waiting_files = [fid for fid, d in self.active_edits.items() if d.get("waiting")]
         if not waiting_files:
             return
@@ -1548,13 +1578,11 @@ class SharePointApp(wx.Frame):
             self.compact_mode = False
             self._update_button_labels(full=True)
 
-        event.Skip()
-
-    def on_status_bar_resize(self, event):
         if hasattr(self, 'gauge') and self.gauge:
             rect = self.status_bar.GetFieldRect(1)
             self.gauge.SetPosition((rect.x + 5, rect.y + 2))
             self.gauge.SetSize((rect.width - 10, rect.height - 4))
+
         event.Skip()
 
     def _update_button_labels(self, full=True):
@@ -1641,7 +1669,7 @@ class SharePointApp(wx.Frame):
             btn.Bind(wx.EVT_BUTTON, self.load_sites)
         elif data:
             def on_click(e, d=data):
-                self._navigate_to_item_data(d, is_breadcrumb=True)
+                self._navigate_to_item_data(d)
                 # Efter navigation, prøv at finde og vælge den i træet
                 wx.CallAfter(self._sync_tree_selection_by_path, d["path"])
                 
@@ -1663,7 +1691,7 @@ class SharePointApp(wx.Frame):
                 self.headers = {'Authorization': f'Bearer {self.access_token}'}
                 return True
         except Exception as e:
-            print(f"Token refresh error: {e}")
+            logger.error(f"Token refresh error: {e}")
             
         self.set_status(self.get_txt("status_login_needed"))
         return False
@@ -1714,13 +1742,12 @@ class SharePointApp(wx.Frame):
         url = "https://graph.microsoft.com/v1.0/sites?search=*"
 
         while url:
-            res = requests.get(url, headers=self.headers)
+            res = _graph_request("GET", url, headers=self.headers, timeout=30)
             if res.status_code == 200:
                 data = res.json()
                 all_sites.extend(data.get('value', []))
                 url = data.get('@odata.nextLink')
                 self.set_status(f"{self.get_txt('status_fetching_sites')} ({len(all_sites)}...)")
-                self.pulse_gauge(True)
             else:
                 break
         
@@ -1771,6 +1798,7 @@ class SharePointApp(wx.Frame):
         if not self.ensure_valid_token(): return
         self.pulse_gauge(True)
         all_children = []
+        url = None
 
         if data['type'] == "SITE":
             url = f"https://graph.microsoft.com/v1.0/sites/{data['id']}/drives"
@@ -1780,12 +1808,11 @@ class SharePointApp(wx.Frame):
             url = f"https://graph.microsoft.com/v1.0/drives/{data['drive_id']}/items/{data['id']}/children"
         
         while url:
-            res = requests.get(url, headers=self.headers)
+            res = _graph_request("GET", url, headers=self.headers, timeout=30)
             if res.status_code == 200:
                 res_data = res.json()
                 all_children.extend(res_data.get('value', []))
                 url = res_data.get('@odata.nextLink')
-                self.pulse_gauge(True)
             else:
                 break
         
@@ -1851,10 +1878,10 @@ class SharePointApp(wx.Frame):
             
         self._navigate_to_item_data(data, tree_item=item)
 
-    def _navigate_to_item_data(self, data, tree_item=None, is_breadcrumb=False):
+    def _navigate_to_item_data(self, data, tree_item=None):
         try:
-            # Race-condition beskyttelse: Hvis vi allerede er der, så stop (undtagen ved brødkrumme-klik)
-            if not is_breadcrumb and getattr(self, 'current_path', None) == data.get("path"):
+            # Race-condition beskyttelse: Hvis vi allerede er der, så stop
+            if getattr(self, 'current_path', None) == data.get("path"):
                 return
                 
             self.current_path = data["path"]
@@ -1884,11 +1911,13 @@ class SharePointApp(wx.Frame):
             self.current_items = []
             self.set_status(self.get_txt("status_loading_content"))
 
-            threading.Thread(target=self._fetch_list_contents_bg, args=(data,), daemon=True).start()
+            self._nav_gen += 1
+            gen = self._nav_gen
+            threading.Thread(target=self._fetch_list_contents_bg, args=(data, gen), daemon=True).start()
         except RuntimeError:
             pass
 
-    def _fetch_list_contents_bg(self, data):
+    def _fetch_list_contents_bg(self, data, nav_gen=None):
         if not self.ensure_valid_token(): return
         self.pulse_gauge(True)
         items_data = []
@@ -1902,7 +1931,7 @@ class SharePointApp(wx.Frame):
             
         first_chunk = True
         while url:
-            res = requests.get(url, headers=self.headers)
+            res = _graph_request("GET", url, headers=self.headers, timeout=30)
             if res.status_code != 200: break
             
             res_data = res.json()
@@ -1934,8 +1963,7 @@ class SharePointApp(wx.Frame):
                     })
             
             items_data.extend(chunk_data)
-            self.set_status(f"Henter... ({len(items_data)} emner)")
-            self.pulse_gauge(True)
+            self.set_status(self.get_txt("status_loading_items").format(count=len(items_data)))
 
             # Chunked UI Update
             if first_chunk:
@@ -1947,7 +1975,7 @@ class SharePointApp(wx.Frame):
             url = res_data.get('@odata.nextLink')
 
         # Finalize
-        wx.CallAfter(self._finalize_list_loading, items_data)
+        wx.CallAfter(self._finalize_list_loading, items_data, nav_gen)
         self.pulse_gauge(False)
 
     def _append_list_items(self, items):
@@ -1960,7 +1988,6 @@ class SharePointApp(wx.Frame):
             img_idx = self.idx_file
             if item['type'] == "FOLDER": img_idx = self.idx_folder
             elif item['type'] == "DRIVE": img_idx = self.idx_drive
-            elif item['type'] == "SITE": img_idx = self.idx_site
             elif item['type'] == "FILE":
                 img_idx = self.get_icon_idx_for_file(item['name'])
             
@@ -1971,8 +1998,10 @@ class SharePointApp(wx.Frame):
             self.list_ctrl.SetItem(idx, 2, size_str)
             self.list_ctrl.SetItem(idx, 3, item['modified'])
 
-    def _finalize_list_loading(self, items_data):
+    def _finalize_list_loading(self, items_data, nav_gen=None):
         if not self: return
+        if nav_gen is not None and nav_gen != self._nav_gen:
+            return  # User navigated away; discard stale results
         self.current_items = items_data
         self.apply_sorting()
         self.set_status(self.get_txt("status_ready"))
@@ -2069,7 +2098,7 @@ class SharePointApp(wx.Frame):
                             idx = self.image_list.Add(bmp)
                             self.ext_icons[ext] = idx
                             return idx
-        except:
+        except Exception:
             pass
 
         self.ext_icons[ext] = self.idx_file
@@ -2228,11 +2257,15 @@ class SharePointApp(wx.Frame):
         file_name = item['name']
         drive_id = item['drive_id']
 
-        if item_id in self.active_edits:
+        with self._edits_lock:
+            already_editing = item_id in self.active_edits
+            at_limit = len(self.active_edits) >= 10
+
+        # UI dialogs are called outside the lock to avoid holding it during blocking calls
+        if already_editing:
             self.show_info(f"'{file_name}' er allerede ved at blive redigeret.", wx.ICON_INFORMATION)
             return
-
-        if len(self.active_edits) >= 10:
+        if at_limit:
             wx.MessageBox("Du kan kun have 10 filer åbne til redigering ad gangen.", "Maksimum grænse nået", wx.OK | wx.ICON_WARNING)
             return
 
@@ -2269,6 +2302,7 @@ class SharePointApp(wx.Frame):
         if not self.ensure_valid_token(): return
         
         edit_event = threading.Event()
+        with self._edits_lock:
             self.active_edits[item_id] = {"name": file_name, "event": edit_event, "waiting": False}
         self.update_edit_ui()
         
@@ -2286,7 +2320,7 @@ class SharePointApp(wx.Frame):
 
             # 2. Download
             self.set_status(self.get_txt("msg_fetching_file", name=file_name))
-            res = requests.get(f"{base_url}/content", headers=self.headers)
+            res = _graph_request("GET", f"{base_url}/content", headers=self.headers, timeout=30)
             if res.status_code != 200:
                 raise Exception(f"{self.get_txt('msg_unknown_error')}: {res.status_code}")
             
@@ -2323,7 +2357,7 @@ class SharePointApp(wx.Frame):
             
             # Checkout
             is_checked_out = False
-            checkout_res = requests.post(f"{base_url}/checkout", headers=self.headers)
+            checkout_res = _graph_request("POST", f"{base_url}/checkout", headers=self.headers, timeout=30)
             if checkout_res.status_code in [200, 201, 204]:
                 is_checked_out = True
                 logger.info(f"Fil {file_name} udtjekket succesfuldt.")
@@ -2356,11 +2390,13 @@ class SharePointApp(wx.Frame):
             else:
                 self.set_status(self.get_txt("msg_waiting_for_file", name=file_name))
                 edit_event.clear()
+                with self._edits_lock:
                     self.active_edits[item_id]["waiting"] = True
                 self.update_edit_ui()
 
                 edit_event.wait()
 
+                with self._edits_lock:
                     if item_id in self.active_edits:
                         self.active_edits[item_id]["waiting"] = False
                 self.update_edit_ui()
@@ -2383,7 +2419,7 @@ class SharePointApp(wx.Frame):
                 
                 if is_checked_out:
                     logger.info(f"Annullerer udtjekning (discardCheckout) for {file_name}...")
-                    res = requests.post(f"{base_url}/discardCheckout", headers=self.headers)
+                    res = _graph_request("POST", f"{base_url}/discardCheckout", headers=self.headers, timeout=30)
                     if res.status_code in [200, 204]:
                         is_checked_out = False
             else:
@@ -2391,14 +2427,14 @@ class SharePointApp(wx.Frame):
                 logger.info(f"Ændring fundet! Uploader {file_name}...")
                 self.set_status(self.get_txt("msg_updating_changes"))
                 with open(local_path, 'rb') as f:
-                    upload_res = requests.put(f"{base_url}/content", headers=self.headers, data=f)
+                    upload_res = requests.put(f"{base_url}/content", headers=self.headers, data=f, timeout=120)
                     if upload_res.status_code not in [200, 201]:
                         raise Exception(f"{self.get_txt('msg_update_failed_code', code=upload_res.status_code)}")
 
                 # 6. Checkin (Kun hvis vi faktisk uploadede noget)
                 if is_checked_out:
                     self.set_status(self.get_txt("msg_checking_in", name=file_name))
-                    res = requests.post(f"{base_url}/checkin", headers=self.headers, json={"comment": "SP Explorer Edit"})
+                    res = _graph_request("POST", f"{base_url}/checkin", headers=self.headers, json={"comment": "SP Explorer Edit"}, timeout=30)
                     if res.status_code in [200, 201, 204]:
                         is_checked_out = False
 
@@ -2406,7 +2442,7 @@ class SharePointApp(wx.Frame):
             try:
                 os.remove(local_path)
                 os.rmdir(working_dir)
-            except:
+            except Exception:
                 pass
                 
             self.set_status(self.get_txt("msg_update_success", name=file_name))
@@ -2420,8 +2456,9 @@ class SharePointApp(wx.Frame):
             if is_checked_out:
                 # Emergency cleanup hvis vi stadig har fat i filen (f.eks. ved crash eller afbrydelse)
                 logger.info(f"Rydder op: Kalder discardCheckout for {file_name}...")
-                requests.post(f"{base_url}/discardCheckout", headers=self.headers)
+                _graph_request("POST", f"{base_url}/discardCheckout", headers=self.headers, timeout=30)
                 
+            with self._edits_lock:
                 if item_id in self.active_edits:
                     del self.active_edits[item_id]
             self.update_edit_ui()

tests/test_review_fixes.py

@@ -0,0 +1,501 @@
+"""
+Unit tests for the code-review bug fixes applied to sharepoint_browser.py.
+
+Covers:
+  C1  - url=None prevents UnboundLocalError in _fetch_tree_children_bg
+  I1  - nav_gen guard in _finalize_list_loading discards stale results
+  I2  - System tab label derivation from STRINGS key
+  I3  - status_loading_items translation key present and formattable
+  C-1 - Refresh calls (nav_gen=None default) always apply their results
+  S-2 - nav_gen=None sentinel is safer than 0
+  S-1 - is_breadcrumb parameter removed from _navigate_to_item_data
+  S2  - Dead SITE branch removed from _append_list_items
+
+All tests run without a live display; wx is imported but no widgets are
+instantiated.
+"""
+
+import sys
+import os
+import inspect
+import unittest
+from unittest.mock import MagicMock, patch
+
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+import sharepoint_browser as sb
+
+
+# ---------------------------------------------------------------------------
+# I2 + I3: STRINGS dictionary
+# ---------------------------------------------------------------------------
+
+class TestStrings(unittest.TestCase):
+
+    def test_system_tab_label_da(self):
+        """I2: Danish settings_logging_group yields 'System' after split/strip."""
+        group = sb.STRINGS["da"]["settings_logging_group"]
+        self.assertEqual(group.split("/")[0].strip(), "System")
+
+    def test_system_tab_label_en(self):
+        """I2: English settings_logging_group yields 'System' after split/strip."""
+        group = sb.STRINGS["en"]["settings_logging_group"]
+        self.assertEqual(group.split("/")[0].strip(), "System")
+
+    def test_status_loading_items_present_da(self):
+        """I3: status_loading_items key exists in Danish STRINGS."""
+        self.assertIn("status_loading_items", sb.STRINGS["da"])
+
+    def test_status_loading_items_present_en(self):
+        """I3: status_loading_items key exists in English STRINGS."""
+        self.assertIn("status_loading_items", sb.STRINGS["en"])
+
+    def test_status_loading_items_format_da(self):
+        """I3: Danish template formats with named {count} argument."""
+        result = sb.STRINGS["da"]["status_loading_items"].format(count=42)
+        self.assertIn("42", result)
+
+    def test_status_loading_items_format_en(self):
+        """I3: English template formats with named {count} argument."""
+        result = sb.STRINGS["en"]["status_loading_items"].format(count=99)
+        self.assertIn("99", result)
+
+    def test_status_loading_items_da_uses_count_kwarg(self):
+        """I3: Danish template uses {count} placeholder (not positional)."""
+        template = sb.STRINGS["da"]["status_loading_items"]
+        self.assertIn("{count}", template)
+
+    def test_status_loading_items_en_uses_count_kwarg(self):
+        """I3: English template uses {count} placeholder (not positional)."""
+        template = sb.STRINGS["en"]["status_loading_items"]
+        self.assertIn("{count}", template)
+
+
+# ---------------------------------------------------------------------------
+# I1 + C-1 + S-2: nav_gen guard in _finalize_list_loading
+# ---------------------------------------------------------------------------
+
+class TestNavGenGuard(unittest.TestCase):
+    """
+    _finalize_list_loading(self, items_data, nav_gen=None)
+
+    Guard logic:
+      nav_gen is None  → always apply (refresh / unconstrained calls)
+      nav_gen == self._nav_gen → apply (matches current navigation)
+      nav_gen != self._nav_gen → discard (stale; user navigated away)
+    """
+
+    def _make_app(self, current_gen: int):
+        """Minimal mock that satisfies _finalize_list_loading's needs."""
+        app = MagicMock()
+        app._nav_gen = current_gen
+        # MagicMock is truthy by default so `if not self` passes
+        return app
+
+    # --- nav_gen=None cases (C-1 / S-2) ---
+
+    def test_none_gen_applies_when_nav_gen_is_1(self):
+        """C-1/S-2: nav_gen=None applies results regardless of _nav_gen."""
+        app = self._make_app(1)
+        items = [{"name": "a"}]
+        sb.SharePointApp._finalize_list_loading(app, items, nav_gen=None)
+        self.assertEqual(app.current_items, items)
+        app.apply_sorting.assert_called_once()
+
+    def test_none_gen_applies_when_nav_gen_is_high(self):
+        """C-1: nav_gen=None still applies when _nav_gen is large."""
+        app = self._make_app(99)
+        items = [{"name": "b"}]
+        sb.SharePointApp._finalize_list_loading(app, items, nav_gen=None)
+        self.assertEqual(app.current_items, items)
+
+    def test_default_gen_arg_applies(self):
+        """C-1: Omitting nav_gen entirely (default=None) always applies."""
+        app = self._make_app(5)
+        items = [{"name": "refresh"}]
+        sb.SharePointApp._finalize_list_loading(app, items)  # no nav_gen kwarg
+        self.assertEqual(app.current_items, items)
+        app.apply_sorting.assert_called_once()
+
+    # --- matching gen (I1, happy path) ---
+
+    def test_matching_gen_applies(self):
+        """I1: Results applied when nav_gen matches _nav_gen."""
+        app = self._make_app(3)
+        items = [{"name": "c"}]
+        sb.SharePointApp._finalize_list_loading(app, items, nav_gen=3)
+        self.assertEqual(app.current_items, items)
+        app.apply_sorting.assert_called_once()
+
+    # --- stale gen cases (I1) ---
+
+    def test_stale_gen_discards_results(self):
+        """I1: Results discarded when nav_gen < _nav_gen (user navigated away)."""
+        app = self._make_app(5)
+        sentinel = object()
+        app.current_items = sentinel
+        sb.SharePointApp._finalize_list_loading(app, [{"name": "old"}], nav_gen=2)
+        self.assertIs(app.current_items, sentinel,
+                      "current_items was overwritten by stale result")
+        app.apply_sorting.assert_not_called()
+
+    def test_future_gen_discards_results(self):
+        """I1: Results discarded when nav_gen > _nav_gen (shouldn't happen, but safe)."""
+        app = self._make_app(3)
+        sentinel = object()
+        app.current_items = sentinel
+        sb.SharePointApp._finalize_list_loading(app, [{"name": "future"}], nav_gen=99)
+        self.assertIs(app.current_items, sentinel)
+        app.apply_sorting.assert_not_called()
+
+    def test_gen_zero_still_discarded_when_nav_gen_nonzero(self):
+        """S-2: nav_gen=0 (old broken default) is now treated as a stale gen, not a pass."""
+        app = self._make_app(1)
+        sentinel = object()
+        app.current_items = sentinel
+        sb.SharePointApp._finalize_list_loading(app, [{"name": "zero"}], nav_gen=0)
+        self.assertIs(app.current_items, sentinel,
+                      "nav_gen=0 should be treated as stale, not as 'no constraint'")
+        app.apply_sorting.assert_not_called()
+
+
+# ---------------------------------------------------------------------------
+# C1: url=None initialization in _fetch_tree_children_bg
+# ---------------------------------------------------------------------------
+
+class TestUrlInitialization(unittest.TestCase):
+
+    def test_url_initialized_to_none_before_conditional(self):
+        """C1: _fetch_tree_children_bg initializes url=None before the if block."""
+        source = inspect.getsource(sb.SharePointApp._fetch_tree_children_bg)
+        # Find the line that sets url = None before the if data['type'] conditional
+        lines = source.splitlines()
+        url_none_idx = next(
+            (i for i, l in enumerate(lines) if "url = None" in l), None
+        )
+        site_if_idx = next(
+            (i for i, l in enumerate(lines)
+             if 'data[\'type\'] == "SITE"' in l or 'data["type"] == "SITE"' in l),
+            None
+        )
+        self.assertIsNotNone(url_none_idx,
+            "_fetch_tree_children_bg has no 'url = None' initializer")
+        self.assertIsNotNone(site_if_idx,
+            "_fetch_tree_children_bg has no SITE type conditional")
+        self.assertLess(url_none_idx, site_if_idx,
+            "'url = None' must appear before the if data['type'] block")
+
+
+# ---------------------------------------------------------------------------
+# S2: Dead SITE branch removed from _append_list_items
+# ---------------------------------------------------------------------------
+
+class TestDeadSiteBranch(unittest.TestCase):
+
+    def test_append_list_items_has_no_site_img_branch(self):
+        """S2: _append_list_items no longer contains the dead SITE image branch."""
+        source = inspect.getsource(sb.SharePointApp._append_list_items)
+        self.assertNotIn(
+            'item[\'type\'] == "SITE"',
+            source,
+            "_append_list_items still contains dead SITE branch"
+        )
+
+
+# ---------------------------------------------------------------------------
+# S-1: is_breadcrumb parameter removed from _navigate_to_item_data
+# ---------------------------------------------------------------------------
+
+class TestIsBreakcrumbRemoved(unittest.TestCase):
+
+    def test_no_is_breadcrumb_param(self):
+        """S-1: _navigate_to_item_data no longer has an is_breadcrumb parameter."""
+        sig = inspect.signature(sb.SharePointApp._navigate_to_item_data)
+        self.assertNotIn(
+            "is_breadcrumb", sig.parameters,
+            "_navigate_to_item_data still declares is_breadcrumb"
+        )
+
+    def test_tree_item_param_still_present(self):
+        """Regression: tree_item parameter was not accidentally removed."""
+        sig = inspect.signature(sb.SharePointApp._navigate_to_item_data)
+        self.assertIn("tree_item", sig.parameters)
+
+
+# ---------------------------------------------------------------------------
+# Task 7: bare except → except Exception, print → logger, basename sanitization
+# ---------------------------------------------------------------------------
+
+class TestTask7BareExcept(unittest.TestCase):
+    """Verify that bare except: clauses have been replaced with except Exception:."""
+
+    def _get_source_lines(self):
+        return inspect.getsource(sb).splitlines()
+
+    def test_no_bare_except_in_load_settings(self):
+        """7a: load_settings() uses except Exception, not bare except."""
+        source = inspect.getsource(sb.load_settings)
+        self.assertNotIn("except:", source,
+            "load_settings still has a bare except:")
+
+    def test_no_bare_except_in_get_txt(self):
+        """7a: get_txt() uses except Exception, not bare except."""
+        source = inspect.getsource(sb.SharePointApp.get_txt)
+        self.assertNotIn("except:", source,
+            "get_txt still has a bare except:")
+
+    def test_no_bare_except_in_get_icon_idx(self):
+        """7a: get_icon_idx_for_file() uses except Exception, not bare except."""
+        source = inspect.getsource(sb.SharePointApp.get_icon_idx_for_file)
+        self.assertNotIn("except:", source,
+            "get_icon_idx_for_file still has a bare except:")
+
+    def test_no_bare_except_in_process_file(self):
+        """7a: process_file() cleanup block uses except Exception, not bare except."""
+        source = inspect.getsource(sb.SharePointApp.process_file)
+        self.assertNotIn("except:", source,
+            "process_file still has a bare except: in cleanup block")
+
+    def test_no_print_in_msal_init(self):
+        """7b: MSAL init error uses logger, not print()."""
+        source = inspect.getsource(sb.SharePointApp.__init__)
+        self.assertNotIn('print(f"MSAL Init Error', source,
+            "__init__ still uses print() for MSAL Init Error")
+
+    def test_no_print_in_ensure_valid_token(self):
+        """7b: ensure_valid_token() uses logger, not print()."""
+        source = inspect.getsource(sb.SharePointApp.ensure_valid_token)
+        self.assertNotIn('print(f"Token refresh error', source,
+            "ensure_valid_token still uses print() for token error")
+
+    def test_basename_in_download_folder_recursive(self):
+        """7c: _download_folder_recursive_sync uses os.path.basename on item name."""
+        source = inspect.getsource(sb.SharePointApp._download_folder_recursive_sync)
+        self.assertIn("os.path.basename", source,
+            "_download_folder_recursive_sync does not sanitize item['name'] with basename")
+
+    def test_basename_in_on_download_clicked(self):
+        """7c: on_download_clicked uses os.path.basename when building dest_path for folders."""
+        source = inspect.getsource(sb.SharePointApp.on_download_clicked)
+        self.assertIn("os.path.basename", source,
+            "on_download_clicked does not sanitize item['name'] with basename for folder downloads")
+
+
+# ---------------------------------------------------------------------------
+# Task 8: all requests.* calls must carry a timeout= parameter
+# ---------------------------------------------------------------------------
+
+class TestNetworkTimeouts(unittest.TestCase):
+    """
+    Every requests.get/post/put/patch/delete call must include timeout=
+    so that background threads cannot hang indefinitely on a stalled network.
+    """
+
+    def _calls_missing_timeout(self):
+        """
+        Return a list of (line_number, line_text) for every requests.*()
+        call in the source file that is missing a timeout= argument.
+
+        Strategy: single-line calls are the norm in this codebase.  We look
+        for lines that contain 'requests.METHOD(' and do NOT also contain
+        'timeout='.  Lines that contain 'timeout=' anywhere on the same line
+        are considered compliant.
+        """
+        import re
+        src_path = os.path.join(
+            os.path.dirname(os.path.dirname(os.path.abspath(__file__))),
+            "sharepoint_browser.py"
+        )
+        # Matches real call sites: assignment or standalone call (not docstrings)
+        pattern = re.compile(
+            r'(=\s*|^\s*)requests\.(get|post|put|patch|delete)\('
+        )
+        missing = []
+        with open(src_path, encoding='utf-8') as fh:
+            for lineno, line in enumerate(fh, 1):
+                stripped = line.lstrip()
+                # Skip comment lines and docstring prose (lines that are plain text)
+                if stripped.startswith('#'):
+                    continue
+                if pattern.search(line) and 'timeout=' not in line:
+                    missing.append((lineno, line.rstrip()))
+        return missing
+
+    def test_all_requests_calls_have_timeout(self):
+        """Task 8: No requests.* call is missing a timeout= parameter."""
+        missing = self._calls_missing_timeout()
+        if missing:
+            details = "\n".join(f"  line {n}: {txt}" for n, txt in missing)
+            self.fail(
+                f"{len(missing)} requests call(s) are missing timeout=:\n{details}"
+            )
+
+
+# ---------------------------------------------------------------------------
+# Task 9: _graph_request helper — retry on 429/503 with Retry-After support
+# ---------------------------------------------------------------------------
+
+class TestGraphRequest(unittest.TestCase):
+    """Unit tests for the _graph_request() module-level helper."""
+
+    def test_helper_exists(self):
+        """Task 9: _graph_request function is defined at module level."""
+        self.assertTrue(
+            callable(getattr(sb, "_graph_request", None)),
+            "_graph_request is not defined in sharepoint_browser"
+        )
+
+    def test_success_on_first_attempt(self):
+        """Task 9: Returns immediately when first response is 200."""
+        mock_resp = MagicMock()
+        mock_resp.status_code = 200
+        with patch("sharepoint_browser.requests.request", return_value=mock_resp) as mock_req:
+            result = sb._graph_request("GET", "https://example.com/", headers={})
+        self.assertEqual(result.status_code, 200)
+        self.assertEqual(mock_req.call_count, 1)
+
+    def test_retries_on_429(self):
+        """Task 9: Retries when response is 429 (rate limited)."""
+        responses = [
+            MagicMock(status_code=429, headers={"Retry-After": "0"}),
+            MagicMock(status_code=429, headers={"Retry-After": "0"}),
+            MagicMock(status_code=200, headers={}),
+        ]
+        with patch("sharepoint_browser.requests.request", side_effect=responses) as mock_req:
+            with patch("sharepoint_browser.time.sleep"):
+                result = sb._graph_request("GET", "https://example.com/", headers={})
+        self.assertEqual(result.status_code, 200)
+        self.assertEqual(mock_req.call_count, 3)
+
+    def test_retries_on_503(self):
+        """Task 9: Retries when response is 503 (service unavailable)."""
+        responses = [
+            MagicMock(status_code=503, headers={}),
+            MagicMock(status_code=200, headers={}),
+        ]
+        with patch("sharepoint_browser.requests.request", side_effect=responses) as mock_req:
+            with patch("sharepoint_browser.time.sleep"):
+                result = sb._graph_request("POST", "https://example.com/", headers={})
+        self.assertEqual(result.status_code, 200)
+        self.assertEqual(mock_req.call_count, 2)
+
+    def test_returns_last_response_after_max_retries(self):
+        """Task 9: Returns last 429 response when all retries are exhausted."""
+        resp_429 = MagicMock(status_code=429, headers={"Retry-After": "0"})
+        responses = [resp_429] * sb._MAX_RETRIES
+        with patch("sharepoint_browser.requests.request", side_effect=responses):
+            with patch("sharepoint_browser.time.sleep"):
+                result = sb._graph_request("GET", "https://example.com/", headers={})
+        self.assertEqual(result.status_code, 429)
+
+    def test_respects_retry_after_header(self):
+        """Task 9: sleep() is called with the Retry-After value from the response."""
+        responses = [
+            MagicMock(status_code=429, headers={"Retry-After": "5"}),
+            MagicMock(status_code=200, headers={}),
+        ]
+        with patch("sharepoint_browser.requests.request", side_effect=responses):
+            with patch("sharepoint_browser.time.sleep") as mock_sleep:
+                sb._graph_request("GET", "https://example.com/", headers={})
+        mock_sleep.assert_called_once_with(5)
+
+    def test_default_timeout_injected(self):
+        """Task 9: timeout=30 is injected when caller does not provide one."""
+        mock_resp = MagicMock(status_code=200, headers={})
+        with patch("sharepoint_browser.requests.request", return_value=mock_resp) as mock_req:
+            sb._graph_request("GET", "https://example.com/", headers={})
+        _, kwargs = mock_req.call_args
+        self.assertEqual(kwargs.get("timeout"), 30)
+
+    def test_caller_timeout_not_overridden(self):
+        """Task 9: Explicit timeout from caller is not overwritten by the helper."""
+        mock_resp = MagicMock(status_code=200, headers={})
+        with patch("sharepoint_browser.requests.request", return_value=mock_resp) as mock_req:
+            sb._graph_request("GET", "https://example.com/", headers={}, timeout=60)
+        _, kwargs = mock_req.call_args
+        self.assertEqual(kwargs.get("timeout"), 60)
+
+    def test_max_retries_constant_exists(self):
+        """Task 9: _MAX_RETRIES constant is defined."""
+        self.assertTrue(
+            hasattr(sb, "_MAX_RETRIES"),
+            "_MAX_RETRIES constant not found in sharepoint_browser"
+        )
+
+    def test_no_sleep_after_final_retry(self):
+        """Fix #1: sleep() is NOT called after the last exhausted attempt."""
+        resp_429 = MagicMock(status_code=429, headers={"Retry-After": "0"})
+        responses = [resp_429] * sb._MAX_RETRIES
+        with patch("sharepoint_browser.requests.request", side_effect=responses):
+            with patch("sharepoint_browser.time.sleep") as mock_sleep:
+                sb._graph_request("GET", "https://example.com/", headers={})
+        # sleep should be called for the first N-1 failures, NOT the last one
+        self.assertEqual(
+            mock_sleep.call_count,
+            sb._MAX_RETRIES - 1,
+            f"sleep() called {mock_sleep.call_count} times; expected {sb._MAX_RETRIES - 1} "
+            f"(no sleep after the final failed attempt)"
+        )
+
+
+# ---------------------------------------------------------------------------
+# Task 10: threading.Lock for active_edits compound operations
+# ---------------------------------------------------------------------------
+
+class TestActiveEditsLock(unittest.TestCase):
+    """Verify that _edits_lock exists and guards all compound active_edits operations."""
+
+    def test_edits_lock_declared_in_init(self):
+        """Task 10: SharePointApp.__init__ creates self._edits_lock."""
+        source = inspect.getsource(sb.SharePointApp.__init__)
+        self.assertIn("_edits_lock", source,
+            "__init__ does not declare _edits_lock")
+
+    def test_edits_lock_is_threading_lock(self):
+        """Task 10: _edits_lock initialisation uses threading.Lock()."""
+        source = inspect.getsource(sb.SharePointApp.__init__)
+        self.assertIn("threading.Lock()", source,
+            "__init__ does not initialise _edits_lock with threading.Lock()")
+
+    def test_open_file_uses_lock(self):
+        """Task 10: open_file() acquires _edits_lock before checking active_edits."""
+        source = inspect.getsource(sb.SharePointApp.open_file)
+        self.assertIn("_edits_lock", source,
+            "open_file does not use _edits_lock")
+
+    def test_process_file_uses_lock(self):
+        """Task 10: process_file() acquires _edits_lock when writing active_edits."""
+        source = inspect.getsource(sb.SharePointApp.process_file)
+        self.assertIn("_edits_lock", source,
+            "process_file does not use _edits_lock")
+
+    def test_process_file_lock_on_initial_assign(self):
+        """Task 10: active_edits[item_id] = ... assignment is inside a lock block."""
+        source = inspect.getsource(sb.SharePointApp.process_file)
+        # Check lock wraps the initial dict assignment
+        lock_idx = source.find("_edits_lock")
+        assign_idx = source.find('self.active_edits[item_id] = ')
+        self.assertGreater(assign_idx, 0,
+            "active_edits assignment not found in process_file")
+        # The lock must appear before the assignment
+        self.assertLess(lock_idx, assign_idx,
+            "_edits_lock must appear before the active_edits assignment in process_file")
+
+    def test_process_file_lock_on_delete(self):
+        """Task 10: del active_edits[item_id] is inside a lock block in process_file."""
+        source = inspect.getsource(sb.SharePointApp.process_file)
+        self.assertIn("del self.active_edits[item_id]", source,
+            "del active_edits[item_id] not found in process_file")
+        # Count lock usages — there should be at least 2
+        lock_count = source.count("_edits_lock")
+        self.assertGreaterEqual(lock_count, 2,
+            f"Expected at least 2 uses of _edits_lock in process_file, found {lock_count}")
+
+    def test_on_done_editing_uses_lock(self):
+        """Task 10: on_done_editing_clicked acquires lock for active_edits iteration."""
+        source = inspect.getsource(sb.SharePointApp.on_done_editing_clicked)
+        self.assertIn("_edits_lock", source,
+            "on_done_editing_clicked does not use _edits_lock")
+
+
+if __name__ == "__main__":
+    unittest.main(verbosity=2)