problems index after adding element to a Jlist

[Kristof Camelbeke]

Hello
I can finally add a new element to a Jlist.
Everything works out fine when I add a new element without selecting something first.
When I have selected something from the Jlist and try to add a new item I get the following errors on the outputscreen :
Connection established successfully!
rowssize = 7
newIndex Jlist = 6
rowssize = 8
Exception occurred during event dispatching:
java.lang.ArrayIndexOutOfBoundsException: -1 < 0
at java.util.Vector.elementAt(Vector.java:427)
at veld.VeldGUI.veldenListSelected1(VeldGUI.java:235)
at veld.VeldGUI.access$300
Here is the code for the actionHandler when I add an new element,FYI I work with vectors and not the DefaultListModel.

valueList.addElement(v.getName());
veldenList.setListData(valueList);
veldenList.repaint();
// Here I put the index of the Jlist to the added element
int newIndex = (rows.size()-1);
veldenList.setSelectedIndex(newIndex);
System.out.println ("newIndex Jlist = " +
newIndex);
Here is my ListSelectionListener when an item is selected :
private void veldenListSelected1(javax.swing.event.ListSelectionEvent evt) {
tfVeldNaam.setText((String)veldenList.getSelectedValue());
cbType.setSelectedIndex(((Veld)rows.elementAt(veldenList.getSelectedIndex())).getType());
tfLengte.setText(new Integer(((Veld)rows.elementAt(veldenList.getSelectedIndex())).getLengte()).toString());
veldDetails.setText(((Veld)rows.elementAt(veldenList.getSelectedIndex())).getOmschrijving());

Thanks
Kristof