Bug 208055 [Markers] Need a sorting method for the markers view
As there is currently no accessible way to change sort order or direction. A menu should be enough.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/provisional/views/markers/MarkerContentGenerator.java
*/
	Collection getMarkerGroups() {
		Collection groups = new HashSet();
		
		addDefinedGroups(groups);
		
		Iterator referencingGroups = MarkerSupportRegistry.getInstance()
				.getMarkerGroups().iterator();
		
		while(referencingGroups.hasNext()){
			MarkerGroup next = (MarkerGroup) referencingGroups.next();
			if(next.isGroupingFor(this.getId()))
				groups.add(next);
		}
		return groups;
	}
	/**
	 * Add the groups defined in the receiver to the collection of groups.
	 * 
	 * @param groups
	 */
	private void addDefinedGroups(Collection groups) {
		IConfigurationElement[] children = configurationElement
				.getChildren(MarkerSupportRegistry.MARKER_SUPPORT_REFERENCE);
		for (int i = 0; i < children.length; i++) {
			
			if (!children[i]
					.getAttribute(MarkerSupportConstants.ATTRIBUTE_TYPE)
					.equals(MarkerSupportRegistry.MARKER_GROUPING))
				continue;