tt.setLayoutData(new GridData(GridData.FILL_BOTH));
toolkit.adapt(tt, true, true);
tt.addListener(SWT.Selection, this);
tt.getTable().addListener(SWT.KeyUp, this); // for delete key
tt.getTable().addListener(SWT.MouseDoubleClick, this); // for edit
tt.addListener(SWT.Expand, this);
tt.addListener(SWT.Collapse, this);
// Make the TableTree's border visible since TableTree is NOT a widget supported
// by FormToolkit. Needed by RedHat Linux
tt.setData(FormToolkit.KEY_DRAW_BORDER, FormToolkit.TREE_BORDER);