Recently, one of our newer Access developers couldn't get her control tips to pop up even though she had assigned values to each of the control's Control Tip Text properties. No matter how much we shook the mouse cursor over the controls, no control tip would pop up.
When we investigated, we discovered that the misbehaving controls were enclosed in rectangles, not contained in Option Groups. This was the right design, since the boxes were drawn for cosmetic purposes, not to manage groups of option buttons. The boxes were simply chiseled outlines with their Back Style properties set to transparent. Even though the rectangles only appeared to enclose the controls, they were in front of them—but because the boxes were transparent, the controls showed through them. We selected each rectangle and used Format | Send to Back so that our text boxes were now on top of the boxes. Our problem disappeared or, rather, our control tips appeared