Bug 299731 [Progress] ProgressMonitorDialog should check for widget state in its async runnable
setOperationCancelButtonEnabled(boolean) should check whether the widget has been disposed or not before invoking setEnabled(boolean). Since this method is called in an asynchronous runnable, there is no guarantee that the widgets are still up when the display gets around to processing them. Display display = new Display(); Shell shell = new Shell(display); shell.setLayout(new GridLayout(1, false)); shell.pack(); shell.open(); ProgressMonitorDialog pmd = new ProgressMonitorDialog(shell); pmd.open(); pmd.run(false, true, new IRunnableWithProgress() { public void run(IProgressMonitor monitor) throws InvocationTargetException, InterruptedException { } }); while (!shell.isDisposed()) { if (!display.readAndDispatch()) display.sleep(); } display.dispose(); Exception in thread "main" org.eclipse.swt.SWTException: Failed to execute runnable (org.eclipse.swt.SWTException: Widget is disposed) at org.eclipse.swt.SWT.error(SWT.java:4068) at org.eclipse.swt.SWT.error(SWT.java:3983) at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:137) at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:3906) at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3527) at org.eclipse.ui.Test.main(Test.java:45) Caused by: org.eclipse.swt.SWTException: Widget is disposed at org.eclipse.swt.SWT.error(SWT.java:4068) at org.eclipse.swt.SWT.error(SWT.java:3983) at org.eclipse.swt.SWT.error(SWT.java:3954) at org.eclipse.swt.widgets.Widget.error(Widget.java:467) at org.eclipse.swt.widgets.Widget.checkWidget(Widget.java:340) at org.eclipse.swt.widgets.Control.setEnabled(Control.java:2928) at org.eclipse.jface.dialogs.ProgressMonitorDialog.setOperationCancelButtonEnabled(ProgressMonitorDialog.java:622) at org.eclipse.jface.dialogs.ProgressMonitorDialog$1.run(ProgressMonitorDialog.java:329) at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35) at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:134) ... 3 more
bundles/org.eclipse.jface/src/org/eclipse/jface/dialogs/ProgressMonitorDialog.java
/**
	 * The cancel button has been pressed.
	 * 
	 * @since 3.0
	 */
	protected void cancelPressed() {
		
		
		
		
		cancel.setEnabled(false);
		progressMonitor.setCanceled(true);
		super.cancelPressed();
	}
	/*
	 * (non-Javadoc) Method declared on Window.
	 */
	/**
	 * The <code>ProgressMonitorDialog</code> implementation of this method
	 * only closes the dialog if there are no currently running runnables.
	 */
	public boolean close() {
		if (getNestingDepth() <= 0) {
			clearCursors();
			return super.close();
		}
		return false;
	}
	/**
	 * Clear the cursors in the dialog.