Bug 155273 [Markers] Visibility of problems view columns should be configurable
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/CachedMarkerBuilder.java
if (monitor.isCanceled())
				return;
			sortAndMakeCategories(new SubProgressMonitor(monitor, 30),
					newMarkers);
			monitor.done();
		} finally {
			building = false;
		}
	}
	/**
	 * Break the marker up into categories
	 * 
	 * @param markers
	 * @param start
	 *            the start index in the markers
	 * @param end
	 *            the last index to check
	 * @param sortIndex -
	 *            the parent of the field
	 * @return MarkerCategory[] or <code>null</code> if we are at the bottom
	 *         of the tree
	 */
	MarkerCategory[] buildHierarchy(MarkerMap markers, int start, int end,
			int sortIndex) {
		MarkerComparator sorter = getComparator();
		if (sortIndex > 0) {
			return null;
		}
		Collection categories = new ArrayList();
		Object previous = null;