We just had a user with a very weird problem on #firefox.de. They couldn't open the download status window, and the mouse over tool-tips for all UI buttons were not working. They were however working in safe mode. We were stumped by the fact that no add-ons were installed and a new profile (reset) didn't help. Finally he tried disabling hw acceleration and that helped (see below for a dump from his about:support with accel disabled). This made things work too. He then updated his GPU drivers and the problem disappeared with acceleration enabled. Based on this I'd suggest to blacklist this driver for GPU accel. Sadly we do not have contact details for this user. DirectWrite aktiviert false (6.1.7601.17789) Geräte-ID 0x0166 GPU #2 aktiv false GPU-beschleunigte Fenster 0/1 Basic Karten-Beschreibung Intel(R) HD Graphics 4000 Karten-RAM Unknown Karten-Treiber igdumd64 igd10umd64 igd10umd64 igdumd32 igd10umd32 igd10umd32 Treiber-Datum 9-26-2012 Treiber-Version 9.17.10.2867 Vendor-ID 0x8086 WebGL-Renderer Google Inc. -- ANGLE (Intel(R) HD Graphics 4000) AzureCanvasBackend cairo AzureContentBackend none AzureFallbackCanvasBackend none

Try updating to the latest Intel 9.18.10.3071 drivers and see if it helps. 32bit https://downloadcenter.intel.com/Detail_Desc.aspx?agr=Y&ProdId=3498&DwnldID=22610 64bit https://downloadcenter.intel.com/Detail_Desc.aspx?agr=Y&ProdId=3498&DwnldID=22605

(In reply to GMA from comment #1) > Try updating to the latest Intel 9.18.10.3071 drivers and see if it helps. You didn't even bother reading and understanding my bug report, didn't you?! Yes, updating fixes the problem on ONE given computer. It still remains a problem for EVERY user who didn't. Hence the suggestion to blacklist hardware acceleration for this particular driver version...