Bug 167170 [Markers] Need to check for duplicate filter names
M3 It is currently possible to enter duplicate filter names
bundles/org.eclipse.ui.ide/src/org/eclipse/ui/views/markers/internal/DialogMarkerFilter.java
* Return the sorter for the receiver.
	 * 
	 * @return ViewerSorter
	 */
	protected ViewerComparator getComparator() {
		return new ViewerComparator() {
			/*
			 * (non-Javadoc)
			 * 
			 * @see org.eclipse.jface.viewers.ViewerComparator#compare(org.eclipse.jface.viewers.Viewer,
			 *      java.lang.Object, java.lang.Object)
			 */
			public int compare(Viewer viewer, Object e1, Object e2) {
				return getComparator().compare(((AbstractNode) e1).getName(),
						((AbstractNode) e2).getName());
			}
		};
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.dialogs.Dialog#okPressed()
	 */
	protected void okPressed() {
		/**
		 * Updates the filter from the UI state. Must be done here rather than
		 * by extending open() because after super.open() is called, the
		 * widgetry is disposed.
		 */
		updateFilterFromUI();