Bug 208101 [Markers] Tasks content has mark completed enabled for non editable tasks
I20071030-0100 Mark completed is enabled for tasks that are not editable
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/provisional/views/markers/ExtendedMarkersView.java
getSite().getPage().addSelectionListener(listener);
		listener.selectionChanged(getSite().getPage().getActivePart(),
				getSite().getPage().getSelection());
		viewer.addOpenListener(new IOpenListener() {
			public void open(OpenEvent event) {
				openSelectedMarkers();
			}
		});
		viewer.getTree().addTreeListener(new TreeAdapter() {
			/*
			 * (non-Javadoc)
			 * 
			 * @see org.eclipse.swt.events.TreeAdapter#treeCollapsed(org.eclipse.swt.events.TreeEvent)
			 */
			public void treeCollapsed(TreeEvent e) {
				removeExpandedCategory((MarkerCategory) e.item.getData());
			}
			/*
			 * (non-Javadoc)
			 * 
			 * @see org.eclipse.swt.events.TreeAdapter#treeExpanded(org.eclipse.swt.events.TreeEvent)
			 */
			public void treeExpanded(TreeEvent e) {
				addExpandedCategory((MarkerCategory) e.item.getData());
			}
		});
		
		viewer.getControl().addHelpListener(new HelpListener() {
			/*
			 * (non-Javadoc)