Remove idle listener when project is disposed (#164)

Author: jimkyndemeyer

src/main/com/intellij/lang/jsgraphql/ide/project/schemastatus/GraphQLSchemasPanel.java

@@ -118,6 +118,9 @@ public boolean isToBuildChildrenInBackground(Object element) {
                     application.executeOnPooledThread(() -> {
                         // run the schema discovery on a pooled to prevent blocking of the UI thread by asking the nodes for heir child nodes
                         // the schema caches will be ready when the UI thread then needs to show the tree nodes
+                        if (myProject.isDisposed()) {
+                            return;
+                        }
                         try {
                             application.runReadAction(() -> {
                                 // use read action to enable use of indexes
@@ -145,6 +148,8 @@ public boolean isToBuildChildrenInBackground(Object element) {
         // update the tree after being idle for a short while
         IdeEventQueue.getInstance().addIdleListener(treeUpdater, 750);
 
+        Disposer.register(myProject, () -> IdeEventQueue.getInstance().removeIdleListener(treeUpdater));
+
         // update tree on schema or config changes
         final MessageBusConnection connection = myProject.getMessageBus().connect();
         connection.subscribe(GraphQLSchemaChangeListener.TOPIC, (schemaVersion) -> {