Add remove button

app.py

@@ -231,6 +231,9 @@ def add_output_click(*struct_ref):
 def remove_output_click(*struct_ref):
     global visible
     print("Removing output", visible)
+    if visible == 0:
+        return struct_ref
+    
     visible -= 1
     structure_texts = struct_ref[::2]
     reference_texts = struct_ref[1::2]