Bug 241209 [Markers] [Problems View] Changing columns in the preferences makes errors disappear from the view
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/ExtendedMarkersView.java
if (memento != null) {
			Scrollable scrollable = (Scrollable) viewer.getControl();
			ScrollBar bar = scrollable.getVerticalBar();
			if (bar != null) {
				Integer position = memento.getInteger(TAG_VERTICAL_POSITION);
				if (position != null)
					bar.setSelection(position.intValue());
			}
			bar = scrollable.getHorizontalBar();
			if (bar != null) {
				Integer position = memento.getInteger(TAG_HORIZONTAL_POSITION);
				if (position != null)
					bar.setSelection(position.intValue());
			}
		}
		
		pageSelectionListener = getPageSelectionListener();
		getSite().getPage().addPostSelectionListener(pageSelectionListener);
		partListener = getPartListener();
		getSite().getPage().addPartListener(partListener);
		pageSelectionListener.selectionChanged(getSite().getPage()
				.getActivePart(), getSite().getPage().getSelection());
		viewer.addOpenListener(new IOpenListener() {
			public void open(OpenEvent event) {
				openSelectedMarkers();
			}
		});
		viewer.getTree().addTreeListener(new TreeAdapter() {
			/*
			 * (non-Javadoc)