Hi, make sure is checked : Go to the Firefox 3 Bar Menu --> Options --> Privacy & Security then under Permissions check the setting to prevent Accessibility Services from accessing your browser.

Go to the 3 Bar Menu then Options --> General --> Performance and untick everything. change the recommended size lower then see how it runs. Note: 1 = No Multiprocessor = slow again. Try 2 Restart Firefox after making these changes please. Note : Hardware Acceleration is for Video Card, Monitor to see if remain off or to turn back on.

Please let us know if this solved your issue or if need further assistance.

Thank you.

I seem to have solved the problem by another method. I removed two addons.

One of them was "undo close tab" which added a button to do that which was already a right click option.

I am afraid I have forgotten what the other deleted addon was.

I now have a lot of tabs open and it is not flashing but I will keep your suggestions in mind in case the problem starts again.

Hi, great. Please do the 1st one though as it should be off if it is on. Also do this to make sure you always have your sessions :

• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer
• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles

Please Select your Answer as the Solution. Thanks .

Alas I spoke too soon. The flickring started again when I opened a lot of tabs.

I already had hardware acceleration turned off.

I did the "prevent Accessibility Services from accessing your browser" but that did not make an impact.

I will try safe mode and turning on addons one by one.

Whenever I open a lot of tabs, this is still happening. https://www.youtube.com/edit?o=U&video_id=G415CR5l6Xc

What did Safe Mode do? What do you see when opening the Browser Console using Ctrl+Shift+J (not Web Console)?