feat: dim other monitors workspaces

bar/widgets/fenster.py

@@ -61,6 +61,9 @@ class FensterWorkspaceButton(Button):
     def set_urgent(self, urgent: bool):
         self._toggle_class("urgent", urgent)
 
+    def set_foreign(self, foreign: bool):
+        self._toggle_class("foreign", foreign)
+
 
 class FensterWorkspaces(Box):
     """Container widget showing a fixed set of workspace bubbles (1..N)."""
@@ -149,11 +152,13 @@ class FensterWorkspaces(Box):
                 button.set_visible_other(False)
                 button.set_urgent(False)
                 button.set_empty(True)
+                button.set_foreign(False)
                 continue
 
             focused = bool(ws.get("focused"))
             visible = bool(ws.get("visible"))
             urgent = bool(ws.get("urgent"))
+            ws_output = ws.get("output")
             window_count = ws.get("window_count", 0)
 
             button.set_active(focused)
@@ -161,6 +166,12 @@ class FensterWorkspaces(Box):
             button.set_visible_other(visible and not focused)
             button.set_urgent(urgent)
             button.set_empty(window_count == 0)
+            # Workspace currently shown on a different output than this bar's.
+            button.set_foreign(
+                self._output is not None
+                and ws_output is not None
+                and ws_output != self._output
+            )
 
         self.show_all()