Bug 214648 [Markers] AttributeMarkerGroupings and GroupingEntries not being cleaned up on removal
We are still leaving the references to AttributeMarkerGroupings and GroupingEntries when we unload
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/views/markers/internal/MarkerGroup.java
class AttributeMapping extends EntryMapping {
		String attribute;
		String attributeValue;
		/**
		 * Create a mapping for an attribute with name attributeName and value
		 * value to the supplied entry.
		 * 
		 * @param entry
		 * @param attributeName
		 * @param value
		 */
		AttributeMapping(MarkerGroupingEntry entry, String attributeName,
				String value) {
			super(entry);
			attribute = attributeName;
			attributeValue = value;
		}
		/*