User Agent: Mozilla/5.0 (X11; Ubuntu; Linux i686; rv:41.0) Gecko/20100101 Firefox/41.0 Build ID: 20150918100354 Steps to reproduce: Open firefox on Ubuntu. Open news tab an random websites or webmail tab. Switching this tabs Actual results: Tabs are not appear correctly but mixed with previous tab and focused tab. On webmail tab when I click on a message, it is selected but not appear selected and the message is blanked. I need to scroll or minimize and maximize firefox to refresh correctly. just refresh does not work every time Expected results: When I click on a tab it appear correctly (and entirely) and previous tab disappear on the screen and appear unselected. On webmail, a message appear selected and when I select an other message. The previous message appear unselected and the new one appear selected. The text of the message appear in the reading div without scrolling or refreshing tab.

Thanks for taking the time to report this! Does the problem still happen if you start Firefox in Safe Mode? (Safe Mode disables extensions and themes, hardware acceleration and some JavaScript stuff in order to exclude some possible reasons for problems. It does not disable plugins which are add-ons.) See http://support.mozilla.com/en-US/kb/Safe+Mode

(In reply to Andre Klapper from comment #1) > Thanks for taking the time to report this! > Does the problem still happen if you start Firefox in Safe Mode? (Safe Mode > disables extensions and themes, hardware acceleration and some JavaScript > stuff in order to exclude some possible reasons for problems. It does not > disable plugins which are add-ons.) See > http://support.mozilla.com/en-US/kb/Safe+Mode Thanks for attention, Yes the problem still happen in safe mode.

Graphics issue. Could you type about:support in the locatin bar and copy here the section "graphics" (accélération graphique). Did it use to work normally with FF40 or older versions?

Oops, another question I forgot: Could you go in about:config and set layers.offmainthreadcomposition.enable=false (restart FF to apply).

(In reply to Loic from comment #4) > Oops, another question I forgot: > > Could you go in about:config and set > layers.offmainthreadcomposition.enable=false (restart FF to apply). Accélération graphique Description de la carte NVIDIA Corporation -- GeForce 9300M GS/PCIe/SSE2 Fenêtres avec accélération graphique 0/1 Basic ID du périphérique GeForce 9300M GS/PCIe/SSE2 ID du vendeur NVIDIA Corporation Prise en charge matérielle pour le décodage H264 false Rendu WebGL NVIDIA Corporation -- GeForce 9300M GS/PCIe/SSE2 Version du pilote 3.3.0 NVIDIA 331.113 windowLayerManagerRemote false Zoom/Panoramique asynchrones aucun AzureCanvasBackend cairo AzureContentBackend cairo AzureFallbackCanvasBackend none AzureSkiaAccelerated 0 Previous versions work correctly. The layers.offmainthreadcomposition.enable=false manipulation seems to correct the bug. Tab (website and webmail) are properly redrawn after this modification. I hope this wil help you to improve FF and I am open to help you in giving other information about this bug if you need. Thanks a lot for your help ! Best regards Francois

I guess it's a dupe.