private void createGTree() {
gTree = new Group(sashForm, SWT.NONE);
gTree.setLayout(new FillLayout());
gTree.setText("Scheduler Elements");
tree = new Tree(gTree, SWT.BORDER);
tree.setMenu(new TreeMenu(tree, dom, this).getMenu());
tree.addListener(SWT.MenuDetect, new Listener() {
public void handleEvent(Event e) {
e.doit = tree.getSelectionCount() > 0;
}
});