public GroupSelector(Vector groupData,
    BibtexBaseFrame baseFrame,
    SidePaneManager manager,
    BibkeeperPrefs prefs) 
{
    
	super(manager);
	ths = this;
	this.prefs = prefs;
	groups = groupData;
	this.manager = manager;
	this.baseFrame = baseFrame;
	double n = (double)(groups.size() - OFFSET);
	while ((n >0) && (n/DIM != Math.floor(n/DIM))) {
	    groups.removeElementAt(groups.size()-1);
	    n = (double)(groups.size() - OFFSET);
	    // If the number of elements is not divisible by DIM, we're 
	    // in trouble, so we must remove one or two elements.
	}
	Dimension butDim = new Dimension(24, 24);
	newButton.setPreferredSize(butDim);
	newButton.setMinimumSize(butDim);
	refresh.setPreferredSize(butDim);
	refresh.setMinimumSize(butDim);
	helpButton.setPreferredSize(butDim);
	helpButton.setMinimumSize(butDim);
	newButton.addActionListener(this);
	refresh.addActionListener(this);
	andCb.addActionListener(this);
	orCb.addActionListener(this);
	newButton.setToolTipText("New group");
	newButton.setToolTipText("Refresh view");
	andCb.setToolTipText("Display only entries belonging to all selected"
			     +" groups.");
	orCb.setToolTipText("Display all entries belonging to one or more "
			    +"of the selected groups.");
	bgr.add(andCb);
	bgr.add(orCb);
	setLayout(gbl);
	SidePaneHeader header = new SidePaneHeader
	    ("Groups", GUIGlobals.groupsIconFile, this);		   
	con.gridwidth = GridBagConstraints.REMAINDER;
	con.fill = GridBagConstraints.BOTH;
	gbl.setConstraints(header, con);
	add(header);
	con.gridwidth = 1;
	con.weightx = 1;
	gbl.setConstraints(newButton, con);
	add(newButton);
	gbl.setConstraints(refresh, con);
	add(refresh);
	con.gridwidth = GridBagConstraints.REMAINDER;
	HelpAction helpAction = new HelpAction(baseFrame.helpDiag,
					       GUIGlobals.groupsHelp,
					       "Help on groups");
	helpButton.addActionListener(helpAction);
	helpButton.setToolTipText("Help on groups");
	gbl.setConstraints(helpButton, con);
	add(helpButton);
	list = new JList();
	revalidateList();
	//list.setSelectedIndex(0);
	list.addListSelectionListener(this);
	list.setPrototypeCellValue("Suitable length");
	// The line above decides on the list's preferred width.
	list.setVisibleRowCount(GUIGlobals.GROUPS_VISIBLE_ROWS);
	list.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
	sp = new JScrollPane
	    (list, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,
	     JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
	con.gridwidth = GridBagConstraints.REMAINDER;
	con.weighty = 1;
	gbl.setConstraints(sp, con);
	add(sp);
	JPanel lower = new JPanel();
	lower.setLayout(gbl);
	lower.setBorder(BorderFactory.createEtchedBorder());
	con.weighty = 0;
	con.anchor = GridBagConstraints.WEST;
	gbl.setConstraints(andCb, con);
	lower.add(andCb);
	gbl.setConstraints(orCb, con);
	lower.add(orCb);
	gbl.setConstraints(lower, con);
	add(lower);
	definePopup();
}

The first element for each group defines which field to use for the quicksearch. The next two define the name and regexp for the group.

 public  void actionPerformed(ActionEvent e) 
{
	if (e.getSource() == refresh) {
	    valueChanged(new ListSelectionEvent(list, 1, 2, false));
	}
	if (e.getSource() == newButton) {
	    GroupDialog gd = new GroupDialog(baseFrame,
					     groups, -1, //groups.size(),
					     prefs.get("groupsDefaultField"));
	    gd.show();
	    if (gd.okPressed()) {
		revalidateList((gd.index()-OFFSET)/DIM +1);
		/*sp.getVerticalScrollBar().setValue
		  (sp.getVerticalScrollBar().getMaximum());*/
		int index = gd.index();
		baseFrame.undoManager.addEdit(new UndoableAddOrRemoveGroup
		    (this, groups, index, true,
		     (String)groups.elementAt(index),
		     (String)groups.elementAt(index+1),
		     (String)groups.elementAt(index+2)));
		baseFrame.markBaseChanged();
		baseFrame.output("Created group '"
				 +gd.name()+"'.");
	    }
	}
	else if (e.getSource() instanceof JCheckBox) {
	    valueChanged(new ListSelectionEvent(list, 1, 2, false));
	}
}

 public  void componentClosing() 
{
	baseFrame.stopShowingGroup();
}

 public  void componentOpening() 
{
	valueChanged(new ListSelectionEvent(list, list.getSelectedIndex(),
					    list.getSelectedIndex(), false));
}

 public  void definePopup() 
{
	
	gropt.add(modifyAction);
	gropt.add(new AbstractAction("Remove") {
		public void actionPerformed(ActionEvent e) {
		    String gname = (String)groups.elementAt
			(OFFSET+DIM*(list.getSelectedIndex()-1)+1);
		    int conf = JOptionPane.showConfirmDialog
			(baseFrame, "Remove group '"+gname+"'?",
			 "Remove group", JOptionPane.YES_NO_OPTION);
		    if (conf == JOptionPane.YES_OPTION) {
			try {
			    int index = OFFSET+DIM*(list.getSelectedIndex()-1);
			    String field = (String)groups.elementAt(index),
				name = (String)groups.elementAt(index+1),
				regexp = (String)groups.elementAt(index+2);
			    for (int i=0; i< DIM; i++)
				groups.removeElementAt(index);	   
			    revalidateList();
			    // Store undo information.
			    baseFrame.undoManager.addEdit
				(new UndoableAddOrRemoveGroup
				 (ths, groups, index, false,
				  field, name, regexp));
			    baseFrame.markBaseChanged();
			    baseFrame.output("Removed group '"
					     +name+"'.");
			} catch (ArrayIndexOutOfBoundsException ex) {
			    System.err.println("Unexpected error when "
					       +"trying to remove group.");
			}
		    }
		}
	    });
	list.addMouseListener(new MouseAdapter() {
		public void mousePressed(MouseEvent e) {
		    int index = list.locationToIndex(e.getPoint());
		    if (index == 0) 
			list.setSelectedIndex(0);
		}
		public void mouseClicked(MouseEvent e) {
		    int index = list.locationToIndex(e.getPoint());
		    if (e.getButton() == MouseEvent.BUTTON3) {
			if ((index  > 0) // Menu for index 0 also?
			    && (index <  list.getModel().getSize())) {
			    list.setSelectedIndex(index);
			    gropt.show(list, e.getPoint().x,
				       list.indexToLocation(index).y);
			}
		    } else {
			if ((index  > 0) && (e.getClickCount() == 2)) {
			    //list.setSelectedIndex(index);
			    modifyAction.actionPerformed
				(new ActionEvent(list, 0, "Modify"));
			}
		    }
		}
	    });
}

 public static int findPos(Vector groups,
    String name) 
{
           
	int index = -1;
	for (int i=OFFSET; i< groups.size(); i+=DIM) {
	    if (name.toLowerCase().compareTo
		(((String)groups.elementAt(i+1)).toLowerCase()) <  0) {
		index = i;
		i = groups.size();
	    }
	}
	if (index == -1)
	    index = groups.size();
	return index;
}

 public  void revalidateList() 
{
	revalidateList(0);
}

 public  void revalidateList(int sel) 
{
	Vector newData = new Vector();
	newData.add(GUIGlobals.SHOW_ALL);
	for (int i=1+OFFSET; i< groups.size(); i+=DIM) {
	    newData.add(groups.elementAt(i));
	}
	list.clearSelection();
	list.setListData(newData);
	list.setSelectedIndex(sel);
}

 public  void valueChanged(ListSelectionEvent e) 
{
	
	if (!e.getValueIsAdjusting() && !list.isSelectionEmpty()) {
	    int[] sel = list.getSelectedIndices();
	    if ((sel.length == 1) && (sel[0] == 0)) {
		// Show all entries.
		baseFrame.stopShowingGroup();
		baseFrame.output("Displaying no group.");
	    } else {
		// Show a search for the keyword of field sel*DIM+OFFSET-1
		// in the vector. The following is analogue with
		// the doSearch() method of SearchPane.
		// We use a search rule set that takes care of multiple groups,
		// in an AND or OR fashion.
		AndOrSearchRuleSet searchRules = 
		    new AndOrSearchRuleSet(andCb.isSelected()); 
		for (int i=0; i< sel.length; i++) if (sel[i]  > 0) {
		    SearchRule rule = new QuickSearchRule
			((String)groups.elementAt(sel[i]*DIM+OFFSET-3),
			 (String)groups.elementAt(sel[i]*DIM+OFFSET-1));
		    searchRules.addRule(rule) ; 
		}
		Hashtable searchOptions = new Hashtable();
		searchOptions.put("option", "dummy");		
		DatabaseSearch search = new DatabaseSearch
		    (searchOptions, searchRules, baseFrame,
		     DatabaseSearch.GROUPSEARCH); 
		search.start(); 
		baseFrame.output("Updated group selection.");
		//groups.elementAt(sel*DIM+OFFSET-DIM+1)+"'.");
	    }
	    //net.sf.bibkeeper.Util.pr("sk: "+list.getSelectedIndex());
	}
}