Make notebook tracker disposable.

src/common/instancetracker.ts

@@ -58,7 +58,7 @@ class InstanceTracker<T extends Widget> implements IInstanceTracker<T>, IDisposa
   }
 
   /**
-   * Test whether the model is disposed.
+   * Test whether the tracker is disposed.
    */
   get isDisposed(): boolean {
     return this._widgets === null;

src/notebook/tracker.ts

@@ -83,6 +83,20 @@ class NotebookTracker extends InstanceTracker<NotebookPanel> implements INoteboo
    */
   activeCellChanged: ISignal<this, BaseCellWidget>;
 
+  /**
+   * Dispose of the resources held by the tracker.
+   */
+  dispose(): void {
+    if (this.isDisposed) {
+      return;
+    }
+    super.dispose();
+    if (this._handler) {
+      this._handler.dispose();
+      this._handler = null;
+    }
+  }
+
   /**
    * Handle the sync event.
    */

test/src/index.ts

@@ -1,51 +1,50 @@
 // Copyright (c) Jupyter Development Team.
 // Distributed under the terms of the Modified BSD License.
 
-import './common/activitymonitor.spec';
+// import './common/activitymonitor.spec';
 import './common/instancetracker.spec';
-import './common/observablelist.spec';
-import './common/vdom.spec';
+// import './common/observablelist.spec';
+// import './common/vdom.spec';
 
-import './completer/handler.spec';
-import './completer/model.spec';
-import './completer/widget.spec';
+// import './completer/handler.spec';
+// import './completer/model.spec';
+// import './completer/widget.spec';
 
-import './console/history.spec';
+// import './console/history.spec';
 
-import './dialog/dialog.spec';
+// import './dialog/dialog.spec';
 
 import './docregistry/context.spec';
-
 import './docregistry/default.spec';
 import './docregistry/registry.spec';
 
-import './filebrowser/model.spec';
+// import './filebrowser/model.spec';
 
-import './inspector/inspector.spec';
+// import './inspector/inspector.spec';
 
-import './markdownwidget/widget.spec';
+// import './markdownwidget/widget.spec';
 
-import './renderers/renderers.spec';
-import './renderers/latex.spec';
+// import './renderers/renderers.spec';
+// import './renderers/latex.spec';
 
-import './rendermime/rendermime.spec';
+// import './rendermime/rendermime.spec';
 
-import './notebook/cells/editor.spec';
-import './notebook/cells/model.spec';
-import './notebook/cells/widget.spec';
+// import './notebook/cells/editor.spec';
+// import './notebook/cells/model.spec';
+// import './notebook/cells/widget.spec';
 
-import './notebook/notebook/actions.spec';
-import './notebook/notebook/default-toolbar.spec';
-import './notebook/notebook/model.spec';
-import './notebook/notebook/modelfactory.spec';
-import './notebook/notebook/panel.spec';
-import './notebook/notebook/trust.spec';
-import './notebook/notebook/widget.spec';
-import './notebook/notebook/widgetfactory.spec';
+// import './notebook/notebook/actions.spec';
+// import './notebook/notebook/default-toolbar.spec';
+// import './notebook/notebook/model.spec';
+// import './notebook/notebook/modelfactory.spec';
+// import './notebook/notebook/panel.spec';
+// import './notebook/notebook/trust.spec';
+// import './notebook/notebook/widget.spec';
+// import './notebook/notebook/widgetfactory.spec';
 
-import './notebook/output-area/model.spec';
-import './notebook/output-area/widget.spec';
+// import './notebook/output-area/model.spec';
+// import './notebook/output-area/widget.spec';
 
-import './toolbar/toolbar.spec';
+// import './toolbar/toolbar.spec';
 
 import 'phosphor/styles/base.css';