The above link is a site currently in development so other elements may get funky from time to time. When viewing the above page as it initially opens, rollover the top navigation and you'll see I have a sub-menu nav working. If you shorten the height of your browser so that a vertical scroll appears, scroll the page down and then try to use the menu. The image rollovers (macromedia swap style) and the submenu divs no longer appear. If you scroll down the page quickly while a submenu is visible, you'll see the submenu move upwards off the screen when it shouldn't move at all. Works correctly in Safari, Firefox and IE 7 (IE 6 doesn't use the fixed position since it doesn't support it).
This appears to be an oldy from back in March. Works fine with Nightly r13354, breaks with Nightly r13372
Created attachment 11526 [details] Reduction
Oops, forgot about the images when adding my reduction attachment. You can also look at the reduction here: http://development.rhubarbproductions.com/webkit/test.html
The "scrolling off the screen" part looks like bug 8788, although that bug is not a regression.
It does seem similar/related to bug 8788. For instance if I resize the browser after scrolling it off, it reappears. If I rollover a button while scrolled down and then resize, the rollover then reappears. So, it's seems tied to repaint issues .
I just read on the other bug: "I don't think this is a repaint bug. Forcing a repaint (by switching to a different tab) doesn't clear the problem. Resizing does, but that also does a layout." My test works in the same fashion and is not cleared by a tab switch, so maybe it's not a paint issue.
Yeah, I don't think either bug is a repaint bug. It's likely that r13372 (fix for bug 7841) made this bug's test case susceptible to bug 8788.
Just checking in to see if anyone has started to take a look at this issue (and the probably related bug 8788 / 9659). It would be really problematic if it lasts to the release version.
Patch for Bug 9659 also resolves this issue.