Add window_title_bar_min_windows option, simplify window_title_bar

- Add window_title_bar_min_windows (0=never, 1=always, 2+=threshold)
  similar to tab_bar_min_tabs, to control when title bars appear
- Remove 'none' choice from window_title_bar so it purely controls
  position (top/bottom); disabling is now via min_windows 0
- Only hide title bar for truly empty template strings, not
  whitespace-only, so users can have intentionally blank bars

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

kitty/layout/base.py

@@ -369,12 +369,12 @@ class Layout:
         self.blank_rects = []
         # Set show_title_bar flag on each visible window before layout
         opts = get_options()
-        title_bar_enabled = opts.window_title_bar != 'none'
+        min_windows = opts.window_title_bar_min_windows
         visible_groups = list(all_windows.iter_all_layoutable_groups(only_visible=True))
         num_visible = len(visible_groups)
         for wg in visible_groups:
             for w in wg.windows:
-                w.show_title_bar = title_bar_enabled and num_visible > 1
+                w.show_title_bar = min_windows > 0 and num_visible >= min_windows
         self.do_layout(all_windows)
 
     def layout_single_window_group(self, wg: WindowGroup, add_blank_rects: bool = True) -> None:

kitty/options/definition.py

@@ -1467,16 +1467,24 @@ actually resize the window itself, but instead, the layout row/column/slot, whic
 in multiple windows getting resized.
 ''')
 
-opt('window_title_bar', 'none',
+opt('window_title_bar', 'top',
-    choices=('none', 'top', 'bottom'),
+    choices=('top', 'bottom'),
     long_text='''
-Show a title bar for each window when there are multiple windows in a tab.
+Control the position of the window title bar relative to the window content.
-The title bar displays the window title and is hidden when only a single window
+Use :opt:`window_title_bar_min_windows` to control when title bars are shown.
-is visible. The value controls the position of the title bar relative to the
-window content. Set to :code:`none` to disable.
 '''
     )
 
+opt('window_title_bar_min_windows', '0',
+    option_type='positive_int',
+    long_text='''
+The minimum number of visible windows in a tab before window title bars
+are shown. A value of :code:`0` means never show. :code:`1` means always
+show. :code:`2` or more means show only when at least that many windows
+are visible. Similar to :opt:`tab_bar_min_tabs` for the tab bar.
+'''
+)
+
 opt('window_title_template', '"{fmt.fg.red}{bell_symbol}{activity_symbol}{fmt.fg.window}{progress_percent}{title}"',
     option_type='tab_title_template',
     long_text='''

kitty/options/parse.py

@@ -1513,7 +1513,10 @@ class Parser:
             raise ValueError(f"The value {val} is not a valid choice for window_title_bar")
         ans["window_title_bar"] = val
 
-    choices_for_window_title_bar = frozenset(('none', 'top', 'bottom'))
+    choices_for_window_title_bar = frozenset(('top', 'bottom'))
+
+    def window_title_bar_min_windows(self, val: str, ans: dict[str, typing.Any]) -> None:
+        ans['window_title_bar_min_windows'] = positive_int(val)
 
     def window_title_bar_active_background(self, val: str, ans: dict[str, typing.Any]) -> None:
         ans['window_title_bar_active_background'] = to_color_or_none(val)

kitty/options/types.py

@@ -37,7 +37,7 @@ choices_for_terminfo_type = typing.Literal['path', 'direct', 'none']
 choices_for_undercurl_style = typing.Literal['thin-sparse', 'thin-dense', 'thick-sparse', 'thick-dense']
 choices_for_underline_hyperlinks = typing.Literal['hover', 'always', 'never']
 choices_for_window_logo_position = choices_for_placement_strategy
-choices_for_window_title_bar = typing.Literal['none', 'top', 'bottom']
+choices_for_window_title_bar = typing.Literal['top', 'bottom']
 choices_for_window_title_bar_align = choices_for_tab_bar_align
 
 option_names = (
@@ -501,6 +501,7 @@ option_names = (
     'window_resize_step_cells',
     'window_resize_step_lines',
     'window_title_bar',
+    'window_title_bar_min_windows',
     'window_title_bar_active_background',
     'window_title_bar_active_foreground',
     'window_title_bar_align',
@@ -700,7 +701,8 @@ class Options:
     window_padding_width: FloatEdges = FloatEdges(left=0, top=0, right=0, bottom=0)
     window_resize_step_cells: int = 2
     window_resize_step_lines: int = 2
-    window_title_bar: choices_for_window_title_bar = 'none'
+    window_title_bar: choices_for_window_title_bar = 'top'
+    window_title_bar_min_windows: int = 0
     window_title_bar_active_background: kitty.fast_data_types.Color | None = None
     window_title_bar_active_foreground: kitty.fast_data_types.Color | None = None
     window_title_bar_align: choices_for_window_title_bar_align = 'center'

kitty/window.py

@@ -1078,8 +1078,8 @@ class Window:
         )
         rendered_title = pts.render(data, progress_percent)
 
-        # If template evaluates to empty/whitespace, zero title bar geometry to hide it
+        # If template evaluates to empty string, zero title bar geometry to hide it
-        if not rendered_title or not rendered_title.strip():
+        if not rendered_title:
             set_window_title_bar_render_data(
                 self.os_window_id, self.tab_id, self.id, pts.screen,
                 0, 0, 0, 0,