Bug 214137 [Markers] Unbound system filters should be bound to problems view.
In 3.3 we supported systemFilters which are not currently picked up by the problems view. We should pick these up for compatiblity.
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/MarkerFieldFilterGroup.java
*/
	static final int ON_SELECTED_ONLY = 1;
	/**
	 * Constant for on working set.
	 */
	static final int ON_WORKING_SET = 4;
	static final String TAG_ENABLED = "enabled"; 
	private static final String TAG_SCOPE = "scope"; 
	private static final String TAG_FIELD_FILTER_ENTRY = "fieldFilter"; 
	private static final String TAG_WORKING_SET = "workingSet"; 
	
	private static String USER = "USER"; 
	/**
	 * Returns the set of projects that contain the given set of resources.
	 * 
	 * @param resources
	 * @return IProject[]
	 */
	static IProject[] getProjects(IResource[] resources) {
		if (resources == null)
			return EMPTY_PROJECT_ARRAY;
		Collection projects = getProjectsAsCollection(resources);
		return (IProject[]) projects.toArray(new IProject[projects.size()]);
	}
	/**
	 * Return the projects for the elements.
	 * 
	 * @param elements
	 *            collection of IResource or IResourceMapping
	 * @return Collection of IProject