Fix stale SelectableStatic mouse events in TUI

frontends/tuiapp_v2.py

@@ -55,6 +55,7 @@ def _ensure_tui_deps() -> None:
     from textual.containers import Horizontal, Vertical, VerticalScroll
     from textual.message import Message
     from textual.screen import ModalScreen
+    from textual.widget import Widget
     from textual.widgets import OptionList, SelectionList, Static, TextArea
     from textual.widgets.option_list import Option
     from textual.widgets.selection_list import Selection
@@ -1140,6 +1141,9 @@ def action_cancel(self) -> None:
 
 class SelectableStatic(Static):
     # Widget.get_selection returns None for non-Text/Content visuals; fall back to render_line.
+    def has_valid_selection_parent(self) -> bool:
+        return isinstance(self.parent, Widget)
+
     def get_selection(self, selection):
         render = getattr(self, "_ga_render", None)
         if render is not None:
@@ -1984,6 +1988,32 @@ def __init__(self, agent_factory: Optional[AgentFactory] = None) -> None:
         except Exception:
             pass
 
+    def _is_stale_selectable_mouse_event(self, event: events.Event) -> bool:
+        if not isinstance(event, (events.MouseDown, events.MouseMove)):
+            return False
+        try:
+            select_widget, select_offset = self.screen.get_widget_and_offset_at(
+                event.x, event.y
+            )
+        except Exception:
+            return False
+        return (
+            select_offset is not None
+            and isinstance(select_widget, SelectableStatic)
+            and not select_widget.has_valid_selection_parent()
+        )
+
+    async def on_event(self, event: events.Event) -> None:
+        if self._is_stale_selectable_mouse_event(event):
+            if isinstance(event, events.MouseDown):
+                try:
+                    self.screen.clear_selection()
+                except Exception:
+                    pass
+            event.stop()
+            return
+        await super().on_event(event)
+
     def compose(self) -> ComposeResult:
         yield Static("", id="topbar")
         with Horizontal(id="body"):

tests/test_tui_stale_selectable.py

@@ -0,0 +1,83 @@
+import asyncio
+import unittest
+
+from textual import events
+from textual.widget import Widget
+
+from frontends.tuiapp_v2 import GenericAgentTUI, SelectableStatic
+
+
+class FakeScreen:
+    def __init__(self, widget, offset):
+        self.widget = widget
+        self.offset = offset
+        self.cleared = False
+
+    def get_widget_and_offset_at(self, x, y):
+        return self.widget, self.offset
+
+    def clear_selection(self):
+        self.cleared = True
+
+
+def make_app(screen):
+    app = GenericAgentTUI()
+    app._screen_stack.append(screen)
+    return app
+
+
+def mouse_down():
+    return events.MouseDown(None, 3, 4, 0, 0, 1, False, False, False, 3, 4)
+
+
+def mouse_move():
+    return events.MouseMove(None, 3, 4, 0, 0, 1, False, False, False, 3, 4)
+
+
+def mouse_up():
+    return events.MouseUp(None, 3, 4, 0, 0, 1, False, False, False, 3, 4)
+
+
+class TuiStaleSelectableTest(unittest.TestCase):
+    def test_stale_selectable_mouse_down_is_stopped_and_clears_selection(self):
+        screen = FakeScreen(SelectableStatic("stale"), object())
+        app = make_app(screen)
+        event = mouse_down()
+
+        self.assertTrue(app._is_stale_selectable_mouse_event(event))
+        asyncio.run(app.on_event(event))
+
+        self.assertTrue(event._stop_propagation)
+        self.assertTrue(screen.cleared)
+
+    def test_stale_selectable_mouse_move_is_stopped_without_clearing_selection(self):
+        screen = FakeScreen(SelectableStatic("stale"), object())
+        app = make_app(screen)
+        event = mouse_move()
+
+        self.assertTrue(app._is_stale_selectable_mouse_event(event))
+        asyncio.run(app.on_event(event))
+
+        self.assertTrue(event._stop_propagation)
+        self.assertFalse(screen.cleared)
+
+    def test_valid_selectable_parent_is_not_treated_as_stale(self):
+        widget = SelectableStatic("mounted")
+        parent = Widget()
+        widget._parent = parent
+        app = make_app(FakeScreen(widget, object()))
+
+        self.assertFalse(app._is_stale_selectable_mouse_event(mouse_down()))
+
+    def test_missing_selection_offset_and_mouse_up_are_not_treated_as_stale(self):
+        widget = SelectableStatic("stale")
+        app = make_app(FakeScreen(widget, None))
+
+        self.assertFalse(app._is_stale_selectable_mouse_event(mouse_down()))
+
+        app = make_app(FakeScreen(widget, object()))
+        self.assertFalse(app._is_stale_selectable_mouse_event(mouse_up()))
+
+
+if __name__ == "__main__":
+    unittest.main()