Bug 136101 [Markers] ProblemsView constantly busy when empty
20060412 The problems view is constantly busy when there are no entries - the tab goes italic all of the time.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/views/markers/internal/MarkerAdapter.java
return;
			if (isShowingHierarchy()) {
				MarkerCategory[] newCategories = buildHierarchy(newMarkers, 0,
						newMarkers.getSize() - 1, 0);
				if (monitor.isCanceled())
					return;
				categories = newCategories;
			}
			lastMarkers = newMarkers;
			monitor.done();
		} finally {
			building = false;
		}
	}
	/**
	 * Return whether or not a hierarchy is showing.
	 * 
	 * @return boolean
	 */
	private boolean isShowingHierarchy() {
		ViewerSorter sorter = view.getViewer().getSorter();
		if (sorter instanceof CategorySorter) {
			return ((CategorySorter) sorter).getCategoryField() != null;
		}
		return false;
	}
	/**
	 * Break the marker up into categories
	 * 
	 * @param markers