Strange Combo problem ... any clues?

I have a page laid out like this (using AW for all four pieces - the dropdowns [aw.ui.combo], tabs [aw.ui.tab], and grid [aw.ui.grid] - note, it is an XML grid):

fuel: [dropdown] status: [dropdown] state [dropdown]
[tab][tab][tab][tab][tab][tab][tab][tab]
GRID ----------------------------------------------------
| | | | |
| | | | |


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The page loads fine and looks great, the dropdowns populate, the tabs function to load other XML data sets in to the grid, and the grid itself is responsive.
Here is the problem. If I click on one of the dropdown lists, it either doesn't paint correctly or it paints BEHIND the tabs or the grid. If I click on it again, it paints correctly. It takes clicking on the dropdowns TWICE to get it to paint correctly (height/width/over the other objects) every time. I can reproduce this.

Anyone have any experiences with the combo widget? I'd post the code, but it is at work (I can post it tomorrow if someone thinks they might be able to help).

Thanks