diff --git a/docs/superpowers/specs/2026-03-20-gui-app-design.md b/docs/superpowers/specs/2026-03-20-gui-app-design.md
index ae377a4..a1b85ab 100644
--- a/docs/superpowers/specs/2026-03-20-gui-app-design.md
+++ b/docs/superpowers/specs/2026-03-20-gui-app-design.md
@@ -52,7 +52,8 @@ def _app_dir() -> str:
         return os.path.dirname(sys.executable)
     else:
         # Dev mode: use script directory (git repo root)
-        return os.path.dirname(os.path.abspath(__file__ + "/../../"))
+        # config.py lives at whisper_app/config.py → two levels up = repo root
+        return os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
 ```
 
 Machine-local config (`config_local.json`) continues to use `%LOCALAPPDATA%\WhisperDictation` (Windows) or `~/.local/share/WhisperDictation` (Linux) — unchanged.
@@ -62,21 +63,25 @@ Machine-local config (`config_local.json`) continues to use `%LOCALAPPDATA%\Whis
 `app.py` owns a `queue.Queue[str]` and a pre-queue buffer list.
 
 ```python
-_log_buffer: list[str] = []   # before queue is ready
+_log_buffer: list[str] = []   # before queue is ready, capped at 500 entries
 _log_queue: queue.Queue | None = None
+_log_lock = threading.Lock()
 
 def log(msg: str) -> None:
-    if _log_queue is not None:
-        _log_queue.put(msg)
-    else:
-        _log_buffer.append(msg)
+    with _log_lock:
+        if _log_queue is not None:
+            _log_queue.put(msg)
+        else:
+            _log_buffer.append(msg)
 
 def set_log_queue(q: queue.Queue) -> None:
     global _log_queue
-    _log_queue = q
-    for msg in _log_buffer:
-        q.put(msg)
-    _log_buffer.clear()
+    with _log_lock:
+        _log_queue = q
+        buffered = list(_log_buffer)
+        _log_buffer.clear()
+    for msg in buffered:          # flush outside the lock to avoid deadlock
+        q.put_nowait(msg)
 ```
 
 All `print()` calls in all modules are replaced with `app.log()`.
@@ -106,6 +111,7 @@ Opened via tray icon left-click or "Anzeigen" menu item. Implemented in `log_win
 - Close button → `withdraw()` (does not quit the app)
 - 🗑 button → clears the text widget
 - Queue polled via `root.after(100, _poll_log_queue)`
+- The tkinter `root` (hidden) is always alive as long as the tray runs — `withdraw()` on the log window does not trigger mainloop exit. The app exits only via the tray "Beenden" menu item.
 
 ## Settings Window — Installation Section
 
@@ -117,9 +123,10 @@ Each integration shows status ("eingerichtet" / "nicht eingerichtet") and two bu
 |---|---|---|
 | Autostart beim Login | `HKCU\Software\Microsoft\Windows\CurrentVersion\Run` | `~/.config/autostart/whisper-dictation.desktop` |
 | Startmenü-Eintrag | `%APPDATA%\Microsoft\Windows\Start Menu\Programs\Whisper Dictation.lnk` | `~/.local/share/applications/whisper-dictation.desktop` |
-| Desktop-Verknüpfung | `%USERPROFILE%\Desktop\Whisper Dictation.lnk` | `~/Desktop/whisper-dictation.desktop` |
+| Desktop-Verknüpfung | `%USERPROFILE%\Desktop\Whisper Dictation.lnk` | XDG: `xdg-user-dir DESKTOP` (fallback: `~/Desktop`) |
 
 Windows `.lnk` files are created via `pywin32` (`win32com.client.Dispatch("WScript.Shell")`).
+`import win32com` must be guarded: `if sys.platform == "win32"` — top-level import is forbidden to avoid import errors on Linux.
 
 **Only available when running as a frozen binary.** In dev mode, the buttons are disabled with a tooltip "Nur im gebauten Binary verfügbar".
 
@@ -141,22 +148,25 @@ a = Analysis(
         'ctranslate2',
         'faster_whisper',
         'sounddevice',
-        'pynput.keyboard._win32',   # Windows
-        'pynput.keyboard._xorg',    # Linux
-    ],
-    datas=[
-        ('config.json', '.'),
-        ('vocabulary.json', '.'),
+        'pynput.keyboard._win32',    # Windows
+        'pynput.keyboard._xorg',     # Linux X11
+        'pynput.keyboard._uinput',   # Linux Wayland
     ],
+    datas=[],  # config.json / vocabulary.json NOT bundled — see below
 )
-exe = EXE(a.pure, ..., console=False, icon='icon.ico')
+pyz = PYZ(a.pure)
+exe = EXE(pyz, a.scripts, ..., console=False, icon='icon.ico')
+coll = COLLECT(exe, a.binaries, a.datas, name='whisper-dictation')
 ```
 
+**config.json / vocabulary.json are NOT bundled via `datas`.**
+They are user-editable files that live next to the binary. `build.py` copies them from the repo root into `dist/whisper-dictation/` after the PyInstaller run. This is the single authoritative location in frozen mode (`os.path.dirname(sys.executable)`).
+
 ### `build.py`
 
-1. Generates `icon.ico` from PIL
+1. Generates `icon.ico` from PIL (must run before PyInstaller — `.spec` references it)
 2. Runs PyInstaller with the `.spec` file
-3. Copies `config.json` and `vocabulary.json` into `dist/whisper-dictation/`
+3. Copies `config.json` and `vocabulary.json` into `dist/whisper-dictation/` **only if they don't already exist there** (to avoid overwriting user edits)
 
 ### Platform requirement
 
@@ -172,6 +182,16 @@ PyInstaller cannot cross-compile. **Build must be run separately on each platfor
 
 Added to `requirements-windows.txt`. Not required on Linux.
 
+## UI Language
+
+All UI labels are in German. "WHISPER DICTATION" in the log panel header is the product name and stays as-is. All other UI text (buttons, section headers, tooltips) is German.
+
+## Implementation Notes
+
+- **Startup crash visibility:** With `console=False`, crashes before the tray appears produce no visible output. Implementer should wrap `main()` in a try/except that writes to a logfile (e.g., `%LOCALAPPDATA%\WhisperDictation\error.log`) as a last resort.
+- **pynput hidden imports:** Only keyboard backends are needed (`_win32`, `_xorg`, `_uinput`). No mouse backends required — hotkeys are keyboard-only.
+- **`_log_buffer` cap:** Enforce max 500 entries; if buffer exceeds cap, drop oldest entry before appending.
+
 ## Out of Scope
 
 - Code signing / notarization