Ensure tabs bar visibility is updated when switching active tab as well

Visibility can change if tab_bar_filter is used and active tab is
changed. See #9328

docs/changelog.rst

@@ -150,6 +150,13 @@ consumption to do the same tasks.
 Detailed list of changes
 -------------------------------------
 
+0.45.1 [future]
+
+- choose-files kitten: Fix JXL image preview not working (:iss:`9323`)
+
+- Fix tab bar rendering glitches when using :opt:`tab_bar_filter` in some
+  circumstances (:iss:`9328`)
+
 0.45.0 [2025-12-24]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

kitty/fast_data_types.pyi

@@ -1069,6 +1069,8 @@ def mark_tab_bar_dirty(os_window_id: int, should_be_shown: bool) -> None:
     pass
 
 
+def is_tab_bar_visible(os_window_id: int) -> bool: ...
+
 def detach_window(os_window_id: int, tab_id: int, window_id: int) -> None:
     pass
 

kitty/state.c

@@ -959,6 +959,18 @@ PYWRAP1(mark_tab_bar_dirty) {
     Py_RETURN_NONE;
 }
 
+PYWRAP1(is_tab_bar_visible) {
+    id_type os_window_id;
+    PA("K", &os_window_id);
+    if (!OPT(tab_bar_hidden)) {
+        WITH_OS_WINDOW(os_window_id)
+            return os_window->has_too_few_tabs ? Py_NewRef(Py_False) : Py_NewRef(Py_True);
+        END_WITH_OS_WINDOW
+    }
+    Py_RETURN_FALSE;
+}
+
+
 PYWRAP1(change_background_opacity) {
     id_type os_window_id;
     float opacity;
@@ -1521,6 +1533,7 @@ static PyMethodDef module_methods[] = {
     MW(set_os_window_chrome, METH_VARARGS),
     MW(focus_os_window, METH_VARARGS),
     MW(mark_tab_bar_dirty, METH_VARARGS),
+    MW(is_tab_bar_visible, METH_VARARGS),
     MW(run_with_activation_token, METH_O),
     MW(change_background_opacity, METH_VARARGS),
     MW(background_opacity_of, METH_O),

kitty/tabs.py

@@ -34,6 +34,7 @@
     get_boss,
     get_click_interval,
     get_options,
+    is_tab_bar_visible,
     last_focused_os_window_id,
     mark_tab_bar_dirty,
     monotonic,
@@ -1148,9 +1149,9 @@ def tab_bar_should_be_visible(self) -> bool:
         return count < 1
 
     def _add_tab(self, tab: Tab) -> None:
-        visible_before = self.tab_bar_should_be_visible
+        visible_before = is_tab_bar_visible(self.os_window_id)
         self.tabs.append(tab)
-        if not visible_before and self.tab_bar_should_be_visible:
+        if visible_before != self.tab_bar_should_be_visible:
             self.tabbar_visibility_changed()
 
     def _set_active_tab(self, idx: int, store_in_history: bool = True) -> None:
@@ -1178,7 +1179,7 @@ def any_window(self) -> Window | None:
         return None
 
     def mark_tab_bar_dirty(self) -> None:
-        should_be_shown = self.tab_bar_should_be_visible and not self.tab_bar_hidden
+        should_be_shown = not self.tab_bar_hidden and self.tab_bar_should_be_visible
         mark_tab_bar_dirty(self.os_window_id, should_be_shown)
         w = self.active_window or self.any_window
         if w is not None:
@@ -1214,11 +1215,14 @@ def set_active_tab(self, tab: Tab, for_keep_focus: Tab | None = None) -> bool:
             idx = self.tabs.index(tab)
         except Exception:
             return False
+        visible_before = is_tab_bar_visible(self.os_window_id)
         self.set_active_tab_idx(idx)
         h = self.active_tab_history
         if for_keep_focus and len(h) > 2 and h[-2] == for_keep_focus.id and h[-1] != for_keep_focus.id:
             h.pop()
             h.pop()
+        if visible_before != self.tab_bar_should_be_visible:
+            self.tabbar_visibility_changed()
         return True
 
     @property
@@ -1418,7 +1422,7 @@ def new_tab(
         return t
 
     def remove(self, removed_tab: Tab) -> None:
-        visible_before = self.tab_bar_should_be_visible
+        visible_before = is_tab_bar_visible(self.os_window_id)
         active_tab_before_removal = self.active_tab
         tabs = tuple(self.tabs_to_be_shown_in_tab_bar)
         remove_tab(self.os_window_id, removed_tab.id)