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 MarkerCategory
		 */
		public MarkerCategory getCategory() {
			return category;
		}
		/*
		 * (non-Javadoc)
		 * 
		 * @see org.eclipse.ui.views.markers.internal.DialogMarkerFilter.AbstractNode#getChildren()
		 */
		public Object[] getChildren() {
			return new Object[0];
		}
		/*
		 * (non-Javadoc)
		 * 
		 * @see org.eclipse.ui.views.markers.internal.DialogMarkerFilter.AbstractNode#getParent()
		 */
		public Object getParent() {
			return category;
		}
		/*
		 * (non-Javadoc)
		 * 
		 * @see org.eclipse.ui.views.markers.internal.DialogMarkerFilter.AbstractNode#hasChildren()
		 */
		public boolean hasChildren() {
			return false;
		}
		/*