don't reschedule async editor loading when the file editor or project is disposed

platform/platform-impl/src/com/intellij/openapi/fileEditor/impl/text/AsyncEditorLoader.java

@@ -91,7 +91,9 @@ public class AsyncEditorLoader {
 
       @Override
       public void onCanceled(@NotNull ProgressIndicator indicator) {
-        scheduleBackgroundLoading(false);
+        if (!Disposer.isDisposed(myTextEditor) || myProject.isDisposed()) {
+          scheduleBackgroundLoading(false);
+        }
       }
     };