I just upgraded to ubuntu 12.04, and it's mostly working. My biggest problem so far: OpenOffice/LibreOffice Calc doesn't show up under the task switcher.

When I pres alt-tab to change windows, I can see all my windows except for any OpenOffice documents I have open. If I minimize other windows, then I can get to my Calc documents, but Alt-Tab just doesn't work.

It only seems to be a problem with Calc. Writer and Impress both work fine.

I do a lot of work in spreadsheets, so this is really messing up my flow. Any thoughts on how to fix it?