Bug 258810 [Markers] Markers for the entire workspace show up when working set empty
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/internal/views/markers/MarkerFieldFilterGroup.java
private boolean isInWorkingSet(IResource resource) {
		if(wSetResources==null)computeWorkingSetResources();
		for (int i = 0; i < wSetResources.length; i++) {
			if(wSetResources[i].getFullPath().isPrefixOf(resource.getFullPath())){
				return true;
			}
		}
		return false;
	}
	/**
	 * 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.
	 */
	private void initializeWorkingSet() {
		IWorkbenchWindow window = PlatformUI.getWorkbench()
				.getActiveWorkbenchWindow();
		if (window != null) {
			IWorkbenchPage page = window.getActivePage();
			if (page != null) {
				setWorkingSet(page.getAggregateWorkingSet());
				if ((PlatformUI.getPreferenceStore()
						.getBoolean(IWorkbenchPreferenceConstants.USE_WINDOW_WORKING_SET_BY_DEFAULT)))
					setScope(ON_WORKING_SET);
			}
		}
	}
	/**
	 * Return whether or not the receiver is enabled.
	 *