I have a pop-up page with two frames. The bottom frame has tables of buttons that vary according to what is in the top frame by having the tables with different z-indexes and changing the visibility property. For the most part this works great. Sometimes, however, when I want z-index 1 to disappear and z-index 4 to appear, z-index 1 is still there. If I close the pop-up window and then re-pop it, it comes up correctly. I'm thinking there is some sort of delay in changing z-index 1 visibility to hidden. Am I on the right track here? Or could it be something else that I'm not thinking of? After my pop-up window is up, the changes with the visibilities works great, it's just the first time it pops up that seems to be the problem.