Start Firefox in <u>[[Safe Mode|Safe Mode]]</u> to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem. *Switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance *Do NOT click the Reset button on the Safe Mode start window *https://support.mozilla.org/kb/Safe+Mode *https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes *https://support.mozilla.org/kb/upgrade-graphics-drivers-use-hardware-acceleration ---- You can try to disable OMTC and leave hardware acceleration in Firefox enabled. *<b>about:config</b> page: <b>layers.offmainthreadcomposition.enabled</b> = false You can open the <b>about:config</b> page via the location/address bar. You can accept the warning and click "I'll be careful" to continue. *http://kb.mozillazine.org/about:config