Bug 214137 [Markers] Unbound system filters should be bound to problems view.
In 3.3 we supported systemFilters which are not currently picked up by the problems view. We should pick these up for compatiblity.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/CachedMarkerBuilder.java
} 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;
		int categoryStart = start;
		Object[] elements = markers.toArray();
		for (int i = start; i <= end; i++) {
			if (previous != null) {