enableHeaderMenu not quite working in some browsers

On my mac (OSX 10.6.4), I’m having some trouble with column hiding. I use enableHeaderMenu, and it works great on many pages. But on some pages (and I can’t figure out what the difference is), when I “right click” on the header, the menu pops up but disappears when I release the mouse. Thus I can’t get over to the menu to use it.

This happens in Safari and Chrome, but not Firefox - it works great in Firefox.

Any idea what might be causing this?

Unfortunately we are not able to reproduce this issue. Can you provide any kind of demo where issue can be reconstructed?