hello jpsiffert, this may be an issue with hardware acceleration. please update your graphics driver and see if this can solve the problem: http://downloadcenter.intel.com/Detail_Desc.aspx?lang=fra&changeLang=true&DwnldId=21776

Thanks madperson, but sadly it hasn't help... ;(

then you could also try disabling hardware acceleration in firefox > options > advanced > general.

Thanks/Danke madperson it seems to work after FF restart!!!!

Still is it so to consider as a FF bug?, beacause none of the other program I often use, does that kind of thing on the extended desktop...

hello i wouldn't consider it a firefox bug, because when hardware acceleration (hwa) is turned on, your graphics hardware is used for rendering parts of the firefox user interface and webpage contents. i suspect it might be an issue with intel's drivers. in this case the only option mozilla would have is to block certain hardware/driver combinations from using hwa in firefox (though normally there is a higher threshold to implement this, like when a driver is crashing the whole browser).

if you want you could report the issue to intel: https://supportmail.intel.com/scripts-emf/welcome.aspx?id=

I have the same problem. Windows 7 (64 Bit), extended desktop, 2 monitor system. I have AMD HD 4800 graphics card with all AMD updates current as of 12/8/2012.

The drop down menus display briefly (flicker) and then are not visible. If I am careful and know the dropdown line I want, I can blindly select it. This happens only on the second monitor on the extended desktop. If I move Mozilla to the primary monitor the same page works correctly.

Disabling the hardware acceleration and restarting Mozilla resolves the issue. While I can use Mozilla, it is still not ready for prime time using hardware acceleration.

Given that it is the only Browser or applicaiton that has this problem with displaying drop down menus on the second monitor, I would suggest that it is either a Mozilla hardware acceleration problem or Mozilla needs to work with the graphics card manufacturers to resolve a problem that only Mozilla seems to have with their drivers.

hello scluce, please also report the issue to amd on the following form: www.amdsurveys.com/se.ashx?s=5A1E27D20B2F3EBB

thank you!