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
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.widgets.Combo;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Tree;
import org.eclipse.swt.widgets.TreeColumn;
import org.eclipse.ui.IWorkingSet;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.dialogs.IWorkingSetSelectionDialog;
/**
 * Dialog which allows user to modify all settings of an
 * org.eclipse.ui.views.MarkerFilter object. Not intended to be subclassed or
 * instantiated by clients.
 */
public abstract class DialogMarkerFilter extends TrayDialog {
	static final int SELECT_ALL_FILTERS_ID = IDialogConstants.CLIENT_ID + 4;
	static final int DESELECT_ALL_FILTERS_ID = IDialogConstants.CLIENT_ID + 5;
	/**
	 * button IDs
	 */
	static final int RESET_ID = IDialogConstants.CLIENT_ID;
	static final int SELECT_WORKING_SET_ID = IDialogConstants.CLIENT_ID + 1;
	static final int SELECT_ALL_ID = IDialogConstants.CLIENT_ID + 2;
	static final int DESELECT_ALL_ID = IDialogConstants.CLIENT_ID + 3;
	private class TypesLabelProvider extends LabelProvider implements