Try the Firefox Safe Mode to see how it works there. The Safe Mode is a troubleshooting mode, which disables most add-ons.

(If you're not using it, switch to the Default theme.)

• You can open the Firefox 4.0+ Safe Mode by holding the Shift key when you use the Firefox desktop or Start menu shortcut.
• Or use the Help menu item and click on the Restart with Add-ons Disabled... menu item while Firefox is running.

Don't select anything right now, just use "'Start in Safe Mode" To exit the Firefox Safe Mode, just close Firefox and wait a few seconds before using the Firefox shortcut (without the Shift key) to open it again. If it is good in the Firefox Safe Mode, your problem is probably caused by an extension, and you need to figure out which one.

Please follow the Troubleshoot extensions, themes and hardware acceleration issues to solve common Firefox problems article for that.

When you figure out what's causing your issues, please let us know. It might help other users who have the same problem.

Firefox Safe Mode, even fx20.0, have the same problem: sometimes when clicking on a Live Bookmark, a transparent outline drops down instead of the normal stories

This may be an issue with version 20, have you tried the current version? (19.0)

I had this problem from 19.0 and I tried to go back to 18.x but I did not found it so I tried 20 and 21 but no luck and I am not alone, please check: http://forums.mozillazine.org/viewtopic.php?f=38&t=2665463

My guess is that patrickjdempsey could be right: "This usually means your graphics hardware is not compatible with the current version of Firefox."

It seems somehow related to Catalyst 13.1 and HD4850 on Win7 x64 as on a laptop with Nvidia drivers and Win7 x64 there is no problem. Still, deselecting hardware accel. has no effect :)

PS: I found the same problem on mouse over "NoScript" button from navigation toolbar (when not in safe mode of course)

This issue has not recurred for about 3 weeks now. Unfortunately I can't quite pinpoint what I changed that fixed it, because I was not actively trying to fix the problem when it went away.

Though I will say that I have been using the Catalyst 13.1 drivers with an HD7970 using Win7 x64.

I've got the same problem. Running FF 19.0 on W7HP x64 on a Core i5 3225 using the integrated HD4000 graphics.

Firefox Extended Support Release 17.0.4 has no problem, so I will stick with it for now as I did not found any solution. By the way Nvidia drivers seems to work ok with the newest Fx version. Sorry to find out that HD4000 is also affected.

I've had this issue for weeks now on my machine at work running Win7 x64. I believe FF just updated the other day which didn't fix the issue... currently running 20.0.1. I tried running in safe mode and the problem still occurs though it seems to occur less frequently but still highly reproducible.

FxESR17.0.5 has no "transparent outline drops down" so go for it as Fx20 and also the new Fx21(beta) still has problems. Maybe Fx22 will get rid of this "transparent windows".

Had this issue on Bookmarks for several versions, still have it on v21.

Only pattern I've noticed is that it most often occurs on a submenu when you have just recently added new bookmark somewhere in that tree.

Say I have bookmark tree like:

Cat1 > Cat2 > Cat3 Cat4 > Cat5 > Cat6 Cat7 > Cat8

I might add a new bookmark to Cat5 or Cat6 and suddenly one just shows as outline next time I open it. However, say it's Cat6 that shows the outline, if I first hover over Cat3 then move straignt down to Cat6 is appears. Very strange, but issue definately only occurs when you have just recently added new bookmark. Possibly caching issue?

I am now on v22 and this issue has not recurred anymore, so go for it!

Still happening in v22