Bug 221521 [Markers] New markers API needs to be pared down
We have too much API in some of the new classes and they can be moved to internals
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/MarkerFieldFilterGroup.java
Policy.handle(e);
			return null;
		}
		return EMPTY_MAP;
	}
	/**
	 * Get the working set for the receiver.
	 * 
	 * @return IWorkingSet
	 */
	IWorkingSet getWorkingSet() {
		return workingSet;
	}
	/**
	 * Return all of the paths in the working set
	 * 
	 * @return Collection
	 */
	private Collection getWorkingSetPaths() {
		if (workingSetPaths == null) {
			workingSetPaths = new HashSet();
			addResourcesAndChildrenPaths(getResourcesInWorkingSet());
		}
		return workingSetPaths;
	}
	/**
	 * Initialise the working set for the receiver. Use the window working set
	 * for the working set and set the scope to ON_WORKING_SET if they are to be
	 * used by default.
	 */