Bug 110998 [Problems] Remove the working set selection and switch to using global working sets
M2 We need to remove the working sets option in the filter and switch to using the current list of working sets. We should move this to a preference that says only "Use Working Sets"
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/views/markers/internal/MarkerSupportRegistry.java
* if there are none.
	 * 
	 * @param markerType
	 * @return String or <code>null</code>
	 */
	public String getCategory(String markerType) {
		if (categories.containsKey(markerType))
			return (String) categories.get(markerType);
		return null;
	}
	/**
	 * Return the TableSorter that corresponds to type.
	 * 
	 * @param type
	 * @return TableSorter
	 */
	public TableSorter getSorterFor(String type) {
		if (hierarchyOrders.containsKey(type))
			return (TableSorter) hierarchyOrders.get(type);
		TableSorter sorter = findSorterInChildren(type, getRootType());
		if (sorter == null)
			return new TableSorter(new IField[0], new int[0], new int[0]);
		return sorter;
	}
	/**
	 * Return the list of root marker types.
	 * 
	 * @return List of MarkerType.
	 */
	private MarkerType getRootType() {