drillDown.setLayoutData(spec);
// Create tree viewer inside drill down.
treeViewer = new TreeViewer(drillDown, SWT.NONE);
drillDown.setChildTree(treeViewer);
ContainerContentProvider cp = new ContainerContentProvider();
cp.showClosedProjects(showClosedProjects);
treeViewer.setContentProvider(cp);
treeViewer.setLabelProvider(WorkbenchLabelProvider
.getDecoratingWorkbenchLabelProvider());
treeViewer.setComparator(new ViewerComparator());
treeViewer.setUseHashlookup(true);