I am facing a very weird problem.

I have a camera view finder display on screen. And at the CBA section I have an "Option" and a "Back" buttons. Very standard settings.

Now The Option menu is very long and usually when I press the button and show the menu, there is scrollbar arrows at the bottom indicating there is more items.

If I apply no effects with the view finder images (i.e. the screen Draw()s very smoothly) the scroll bar arrow shows normally. However when I apply some effects with the view finder bitmap, (i.e. the view finder starts to get a bit delayed) the scroll bar disappers!! (And sometimes it shoulds 1 or 2 seconds later after i press open the menu)

I suspect the CPU power is always busy and the "Draw scroll bar arrow" action is not 1st pirority so the control doesn't have time to draw it out? Is there a way to force the UI to draw the scroll bar out?