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
}
			}
		}
		/**
		 * Sets the specified working set.
		 * 
		 * @param workingSet
		 *            the working set
		 */
		void setWorkingSet(IWorkingSet workingSet) {
			button.setData(workingSet);
			if (workingSet != null) {
				button.setText(NLS.bind(
						MarkerMessages.filtersDialog_workingSet, workingSet
								.getLabel()));
			} else {
				button.setText(MarkerMessages.filtersDialog_noWorkingSet);
			}
		}
		void setEnabled(boolean enabled) {
			button.setEnabled(enabled);
			selectButton.setEnabled(enabled);
		}
	}
	/**
	 * AbstractNode is the abstract superclass of the node elements for
	 * MarkerTypes.
	 * 
	 */
	private abstract class AbstractNode {