Bug 294303 [Markers] 'Queuing Viewer Updates' in Problems view
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/ExtendedMarkersView.java
setContentDescription(message != null ? message
							: getStatusMessage());
					if (updateLabels) {
						updateCategoryLabels();
					}
					return Status.OK_STATUS;
			}
		};
		job.setPriority(Job.INTERACTIVE);
		job.schedule();
	}
	void updateCategoryLabels() {
		if (builder.isShowingHierarchy()) {
			MarkerCategory[] categories = builder.getClonedMarkers().getCategories();
			boolean refreshing = builder.isBuilding()
					|| builder.getMarkerListener().isUpdating() 
					|| builder.getMarkerListener().workspaceBuilding();
			for (int i = 0; i < categories.length; i++) {
				categories[i].refreshing = refreshing;
			}
			if (categories != null && categories.length > 1) {
				viewer.update(categories, null);
			}
		}
	}
	/**
	 * @return the viewer
	 */
	TreeViewer getViewer() {
		return viewer;