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
* @param marker
	 * @return MarkerItem or <code>null<code> if it cannot be found
	 */
	MarkerItem getMarkerItem(IMarker marker) {
		if (refreshingMarkers())
			return null;
		return currentMap.getMarkerItem(marker);
	}
	/**
	 * Get the name for the preferences for the receiver.
	 * 
	 * @return String
	 */
	private String getMementoPreferenceName() {
		return getClass().getName() + viewId;
	}
	/**
	 * Return the primary sort field
	 * 
	 * @return MarkerField
	 */
	MarkerField getPrimarySortField() {
		return getComparator().getPrimarySortField();
	}
	/**
	 * Get the sort direction of field
	 * 
	 * @param field
	 * @return int one of {@link MarkerComparator#ASCENDING} or
	 *         {@link MarkerComparator#DESCENDING}