User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.13) Gecko/20101203 Firefox/3.6.13 Build Identifier: 4.0b10pre (2011-01-25) This only happened to me once still, but it's there, so it needs to be checked out, if at all possible. Reproducible: Always Steps to Reproduce: 1. Open the Firefox menu 2. Put your mouse over a split menu arrow (the > thingy) 3. Wait a bit for the submenu to open Actual Results: The arrow button never got to hover state, not immediately after the mouse got over it, and not after the submenu opened Expected Results: The arrow button should get into hover state immediately, and keep that way. I must stress that this ONLY HAPPENED ONCE, and even though I can't make it happen again, there's something wrong with the CSS code or whatever.

I can reproduce it, but in a weird way: 1 - Locate a place with 2 split menu next to each other (option/help) 2 - Move from one menu to another quickly until both sub-menu flashes on after another (probably Bug628743) 3 - Jump to a ">" 4 - Try again (it's not a 100% hits) Hope this helps.

This will probably be fixed by bug 633656, since there should not be a state where the main menuitem is highlighted but the arrow is not.

Build identifier: Mozilla/5.0 (Windows NT 5.1; rv:6.0a1) Gecko/20110502 Firefox/6.0a1 This is kinda still a problem. STR: 1. Open Firefox menu 2. Hover over "Downloads" 3. Quickly go over "History" (not the triangle) 4. Immediatly move mouse to the right to enter split menu 5. See the triangle without any highlight flash for 0.5 second

This UI doesn't exist anymore.