void PropertyData(Gtk.TreeViewColumn tree_column, Gtk.CellRenderer cell, Gtk.TreeModel model, Gtk.TreeIter iter)
{
CellRendererProperty rc = (CellRendererProperty) cell;
bool group = (bool) model.GetValue (iter, 2);
if (group) {
rc.SetData (null, null, null);
} else {
PropertyDescriptor prop = (PropertyDescriptor) model.GetValue (iter, 1);
PropertyEditorCell propCell = PropertyEditorCell.GetPropertyCell (prop);
InstanceData idata = (InstanceData) model.GetValue (iter, 3);
propCell.Initialize (tree, prop, idata.Instance);
rc.SetData (idata.Instance, prop, propCell);
}
}