diff --git a/tests/test_lazymodule_filedialog_fallback.py b/tests/test_lazymodule_filedialog_fallback.py
new file mode 100644
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+++ b/tests/test_lazymodule_filedialog_fallback.py
@@ -0,0 +1,101 @@
+"""
+Regression test for: AttributeError: module 'tkinter' has no attribute 'filedialog'
+
+On some Python installs (e.g., embedded distributions, or installs where
+the Tcl/Tk runtime is missing), the `tkinter` package imports cleanly but
+the `tkinter.filedialog` sub-module fails to load. The original `_LazyModule`
+in src/gui_2.py used `getattr(tkinter, 'filedialog')` which raises a
+confusing AttributeError at the call site. With 14 call sites in
+render_projects_panel, render_workspace_settings_hub, render_fonts_panel,
+and render_gemini_cli_settings, this AttributeError spammed the GUI's
+stderr at 60fps whenever the Project Settings window was open.
+
+The fix must make `_LazyModule` fall back to a stub that mimics
+`tkinter.filedialog`'s public API (askopenfilename, askdirectory,
+asksaveasfilename, askopenfilenames) so the GUI does not crash.
+
+This test uses a deliberately-missing sub-module to exercise the fallback
+path, making it deterministic across Python installs.
+"""
+import pytest
+import importlib
+
+from src.gui_2 import _LazyModule
+
+
+def test_lazymodule_falls_back_to_stub_on_attribute_error() -> None:
+ """
+ Resolution must NOT raise AttributeError when the sub-module is
+ missing. Instead, _resolve() must return a stub that exposes the
+ public filedialog API. Before the fix, this test fails with
+ AttributeError: module 'os' has no attribute 'this_submodule_does_not_exist'.
+ """
+ bad = _LazyModule("os", "this_submodule_does_not_exist")
+ resolved = bad._resolve()
+ assert resolved is not None
+ assert hasattr(resolved, "askopenfilename")
+ assert hasattr(resolved, "askdirectory")
+ assert hasattr(resolved, "asksaveasfilename")
+ assert hasattr(resolved, "askopenfilenames")
+
+
+def test_lazymodule_stub_returns_empty_strings() -> None:
+ """
+ The stub functions must return safe empty values:
+ - askopenfilename, askdirectory, asksaveasfilename: empty string ""
+ - askopenfilenames: empty tuple ()
+ This ensures downstream code that does `if p and p not in app.x:`
+ or `if paths:` treats the missing-dialog as a no-op.
+ """
+ bad = _LazyModule("os", "this_submodule_does_not_exist")
+ resolved = bad._resolve()
+ assert resolved.askopenfilename() == ""
+ assert resolved.askdirectory() == ""
+ assert resolved.asksaveasfilename() == ""
+ assert resolved.askopenfilenames() == ()
+
+
+def test_lazymodule_stub_ignores_kwargs() -> None:
+ """
+ The stub must accept the same kwargs the real tkinter.filedialog
+ accepts (title, filetypes, defaultextension, initialdir) and return
+ the empty sentinel. This prevents TypeError if a call site passes
+ kwargs that the stub does not know about.
+ """
+ bad = _LazyModule("os", "this_submodule_does_not_exist")
+ resolved = bad._resolve()
+ assert resolved.askopenfilename(title="x", filetypes=[("All", "*.*")]) == ""
+ assert resolved.askdirectory(title="y", initialdir="/") == ""
+ assert resolved.asksaveasfilename(title="z", defaultextension=".toml", filetypes=[("TOML", "*.toml")]) == ""
+ assert resolved.askopenfilenames(filetypes=[("Image", "*.png")]) == ()
+
+
+def test_lazymodule_real_filedialog_resolves_when_tkinter_works() -> None:
+ """
+ On a working tkinter install (with Tcl/Tk runtime), the
+ `_LazyModule("tkinter", "filedialog")` instance must resolve to the
+ real tkinter.filedialog module. This is the smoke test: if tkinter
+ is healthy, the lazy import works as before.
+ """
+ import tkinter as tk_root
+ try:
+  import tkinter.filedialog as real_filedialog
+ except (ImportError, AttributeError, tk_root.TclError):
+  pytest.skip("tkinter.filedialog not available in this Python install")
+ lazy = _LazyModule("tkinter", "filedialog")
+ resolved = lazy._resolve()
+ assert resolved is real_filedialog
+
+
+def test_lazymodule_real_filedialog_does_not_raise_attribute_error() -> None:
+ """
+ On a working tkinter install, calling .askopenfilename() through the
+ lazy module must not raise AttributeError. (Tests the call path
+ used by 14 call sites in render_projects_panel etc.)
+ """
+ lazy = _LazyModule("tkinter", "filedialog")
+ resolved = lazy._resolve()
+ assert hasattr(resolved, "askopenfilename")
+ assert hasattr(resolved, "askdirectory")
+ assert hasattr(resolved, "asksaveasfilename")
+ assert hasattr(resolved, "askopenfilenames")