frobar: Fix empty container name

hm/desktop/frobar/frobar/providers.py

@@ -42,7 +42,10 @@ class I3WindowTitleProvider(SingleSectionProvider):
     # TODO FEAT To make this available from start, we need to find the
     # `focused=True` element following the `focus` array
     def on_window(self, i3: i3ipc.Connection, e: i3ipc.Event) -> None:
-        self.section.setText(clip(e.container.name, 60))
+        if e.container.name is None:
+            self.section.setText(None)
+        else:
+            self.section.setText(clip(e.container.name, 60))
 
     async def run(self) -> None:
         await super().run()