Bug 214649 [Markers] Allow markerAttributeGroupings and markerGroups to be specified within contentGenerators
With everything at the top level it is hard to see the relation to a contentGenerator and the groups and attribute groupings. These should be sub elements a la menus.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/CachedMarkerBuilder.java
if (getCategoryGroup() != null)
				field = getCategoryGroup().getMarkerField();
			comparator = new MarkerComparator(field, generator.getAllFields());
			comparator.restore(this.memento);
		}
		return comparator;
	}
	/**
	 * Return the elements in the adapter.
	 * 
	 * @return Object[]
	 */
	MarkerItem[] getElements() {
		if (refreshingMarkers()) {
			return MarkerSupportInternalUtilities.EMPTY_MARKER_ITEM_ARRAY;
		}
		if (isShowingHierarchy() && categories != null) {
			return categories;
		}
		return currentMap.toArray();
	}
	/**
	 * Return the currently enabled filters.
	 * 
	 * @return Collection of MarkerFieldFilterGroup
	 */
	Collection getEnabledFilters() {
		if (enabledFilters == null) {
			enabledFilters = new HashSet();
			Iterator filtersIterator = getAllFilters().iterator();