@Nullable
 private NameLocationPair editExtLocation(Object o) {
   NameLocationPair pair = (NameLocationPair) o;
   MapExternalResourceDialog dialog =
       new MapExternalResourceDialog(pair.getName(), myProject, null, pair.getLocation());
   if (!dialog.showAndGet()) {
     return null;
   }
   setModified(true);
   return new NameLocationPair(dialog.getUri(), dialog.getResourceLocation(), pair.myShared);
 }
 @Override
 public void setValue(Object aValue, NameLocationPair data, int columnIndex) {
   data.myShared = !((Boolean) aValue).booleanValue();
 }