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
addEntry(markerType, new AttributeMapping(entry, attribute,
				attributeValue));
	}
	/**
	 * Remove the entry from all of the entries in the receiver.
	 * 
	 * @param entry
	 */
	public void remove(MarkerGroupingEntry entry) {
		Iterator entries = typesToMappings.values().iterator();
		Collection removeCollection = new ArrayList();
		while (entries.hasNext()) {
			Collection mappings = (Collection) entries.next();
			Iterator mappingsIterator = mappings.iterator();
			while (mappingsIterator.hasNext()) {
				EntryMapping next = (EntryMapping) mappingsIterator.next();
				if (next.groupingEntry.equals(entry)) {
					removeCollection.add(next);
				}
			}
			mappings.removeAll(removeCollection);
			removeCollection.clear();
		}
	}
	/**
	 * Set entry and the default entry for the supplied markerType.
	 * 
	 * @param markerType
	 * @param entry
	 */