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 cursor used in the cancel button;
	 */
	protected Cursor arrowCursor;
	/**
	 * The cursor used in the shell;
	 */
	private Cursor waitCursor;
	/**
	 * Flag indicating whether to open or merely create the dialog before run.
	 */
	private boolean openOnRun = true;
	/**
	 * Internal progress monitor implementation.
	 */
	private class ProgressMonitor implements IProgressMonitorWithBlocking {
		private String fSubTask = "";
		private volatile boolean fIsCanceled;
		/**
		 * is the process forked
		 */
		protected boolean forked = false;
		/**
		 * is locked
		 */
		protected boolean locked = false;
		public void beginTask(String name, int totalWork) {
			if (progressIndicator.isDisposed()) {
				return;
			}