diff --git a/kitty/layout/base.py b/kitty/layout/base.py
index ed1f164ee..e2c3c0144 100644
--- a/kitty/layout/base.py
+++ b/kitty/layout/base.py
@@ -218,7 +218,7 @@ class Layout:
         self.remove_all_biases()
 
     def bias_increment_for_cell(self, is_horizontal: bool) -> float:
-        self._set_dimensions()
+        self.set_dimensions()
         if is_horizontal:
             return (lgd.cell_width + 1) / lgd.central.width
         return (lgd.cell_height + 1) / lgd.central.height
@@ -297,11 +297,11 @@ class Layout:
             is_visible = window is active_window or (is_group_leader and not self.only_active_window_visible)
             window.set_visible_in_layout(is_visible)
 
-    def _set_dimensions(self) -> None:
+    def set_dimensions(self) -> None:
         lgd.central, tab_bar, vw, vh, lgd.cell_width, lgd.cell_height = viewport_for_window(self.os_window_id)
 
     def __call__(self, all_windows: WindowList) -> None:
-        self._set_dimensions()
+        self.set_dimensions()
         self.update_visibility(all_windows)
         self.blank_rects = []
         self.do_layout(all_windows)
diff --git a/kitty/tabs.py b/kitty/tabs.py
index 97501d523..b19d3f509 100644
--- a/kitty/tabs.py
+++ b/kitty/tabs.py
@@ -204,6 +204,7 @@ class Tab:  # {{{
         if tm is not None:
             w = self.active_window
             ly = self.current_layout
+            ly.set_dimensions()
             self.borders(
                 all_windows=self.windows,
                 current_layout=ly, extra_blank_rects=tm.blank_rects,