Bug 330803 SWTException from tool item dropdowns after closing/reopening perspectives
1. Click the 'Run' tool item's dropdown arrow. 2. Window > Close Perspective 3. Window > Open Perspective > Other... > Java 4. Repeat step 1. org.eclipse.swt.SWTException: Widget is disposed at org.eclipse.swt.SWT.error(SWT.java:4091) at org.eclipse.swt.SWT.error(SWT.java:4006) at org.eclipse.swt.SWT.error(SWT.java:3977) at org.eclipse.swt.widgets.Widget.error(Widget.java:468) at org.eclipse.swt.widgets.Widget.checkWidget(Widget.java:340) at org.eclipse.swt.widgets.Menu.setLocation(Menu.java:1427) at org.eclipse.e4.ui.workbench.renderers.swt.ToolItemRenderer$5.widgetSelected(ToolItemRenderer.java:315) at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:234) at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84) at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053) at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4084) at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3675) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$6.run(PartRenderingEngine.java:780) at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:696) at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:91)
bundles/org.eclipse.e4.ui.workbench.renderers.swt/src/org/eclipse/e4/ui/workbench/renderers/swt/ToolItemRenderer.java
IEclipseContext context = getContext(model);
			EBindingService bs = (EBindingService) context
					.get(EBindingService.class.getName());
			ParameterizedCommand cmd = handledItem.getWbCommand();
			if (cmd == null) {
				cmd = generateParameterizedCommand(handledItem, context);
			}
			TriggerSequence sequence = bs.getBestSequenceFor(handledItem
					.getWbCommand());
			if (sequence != null) {
				text = text + '\t' + sequence.format();
			}
			item.setText(text);
		} else {
			if (text == null) {
				text = ""; 
			}
			item.setText(text);
		}
	}
	private String getToolTipText(MItem item) {
		String text = item.getTooltip();
		if (item instanceof MHandledItem) {
			MHandledItem handledItem = (MHandledItem) item;
			IEclipseContext context = getContext(item);
			EBindingService bs = (EBindingService) context
					.get(EBindingService.class.getName());
			ParameterizedCommand cmd = handledItem.getWbCommand();
			if (cmd == null) {
				cmd = generateParameterizedCommand(handledItem, context);