To clarify, I think there are two problems here. The rightmost screen shows that it is possible to add controls onto the properties screen.
I can't remember if it was possible previously but you can now, I've tried it on my iPAQ so it's not a 6.5.3 issue.
The second problem is obviously that the OK button is hidden by the menu bar as it has now moved to the bottom of the screen. I would assume that applications are meant to run unchanged on 6.5.3 so I would have thought there must be an alternative as other programs, like Microsoft Pocket Streets and my other mapping program have similar menus at the bottom of the screen.