diff --git a/addons/diff-margin/plugin.gd b/addons/diff-margin/plugin.gd
index 702c9b9..c7fe195 100644
--- a/addons/diff-margin/plugin.gd
+++ b/addons/diff-margin/plugin.gd
@@ -104,8 +104,9 @@ func _on_editor_script_focus_entered():
 
 func _on_editor_script_changed(_script: Script = null):
   if _gutter_id != -1:
-    _editor.gutter_clicked.disconnect(_on_gutter_clicked)
-    _editor.remove_gutter(_gutter_id)
+    if is_instance_valid(_editor):
+      _editor.gutter_clicked.disconnect(_on_gutter_clicked)
+      _editor.remove_gutter(_gutter_id)
 
   var script_editor = EditorInterface.get_script_editor()
   if not script_editor or not script_editor.get_current_editor():