prune slot stacks

nicegui/globals.py

@@ -64,6 +64,12 @@ def get_slot_stack() -> List['Slot']:
     return slot_stacks[task_id]
 
 
+def prune_slot_stack() -> None:
+    task_id = get_task_id()
+    if not slot_stacks[task_id]:
+        del slot_stacks[task_id]
+
+
 def get_slot() -> 'Slot':
     return get_slot_stack()[-1]
 

nicegui/slot.py

@@ -21,6 +21,7 @@ class Slot:
 
     def __exit__(self, *_):
         globals.get_slot_stack().pop()
+        globals.prune_slot_stack()
         self.lazy_update()
 
     def lazy_update(self) -> None: