Is there a way to get rid of the big red X (Cancel) and the green arrow (Return)?

I think that you'll find (most of) the automatic menus and toolbar buttons in the --- WIDGET file. If you don't want them to show up, just delete them from --- WIDGET in the Pre-Display event point (or disable them if you want to see them but you don't want them to do anything). If you want a more pervasive solution, you can hook the --- STANDARD TOOLBARS input process.