Bug 127629 [Markers] problems view: keep selection stable
I20050214-0010 1. Select a grouping (e.g. Java problem type) and select a marker inside 2. Switch to another grouping Selection is gone. Same when - changing filter - a build adds new marker (in a different file)
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/views/markers/internal/MarkerView.java
* 
		 * @see org.eclipse.ui.progress.WorkbenchJob#shouldRun()
		 */
		public boolean shouldRun() {
			return PlatformUI.isWorkbenchRunning();
		}
		/*
		 * (non-Javadoc)
		 * 
		 * @see org.eclipse.core.runtime.jobs.Job#belongsTo(java.lang.Object)
		 */
		public boolean belongsTo(Object family) {
			return MARKER_UPDATE_FAMILY == family;
		}
	}
	MarkerProcessJob markerProcessJob = new MarkerProcessJob();
	private class UpdateJob extends WorkbenchJob {
		private Collection categoriesToExpand = new HashSet();
		UpdateJob() {
			super(MarkerMessages.MarkerView_queueing_updates);
			setSystem(true);
		}
		/*
		 * (non-Javadoc)
		 * 
		 * @see org.eclipse.ui.progress.UIJob#runInUIThread(org.eclipse.core.runtime.IProgressMonitor)
		 */
		public IStatus runInUIThread(IProgressMonitor monitor) {
			if (getViewer().getControl().isDisposed()) {
				return Status.CANCEL_STATUS;