if (_os == OS.MAC) {
// TODO: figure out why this hack allows native text fields to work on Mac
// In my investigation so far, the hack has to be added on startup, moveAbove must be
// called and the bounds must overlap with the canvas'.
Composite hack = new Composite(_overlay, SWT.NONE);
hack.moveAbove(null);
// make the hack small and black; TODO: expose color to apps if this hack is permanent
hack.setBounds(0, 0, 1, 1);
hack.setBackground(new Color(display(), 0, 0, 0));
}