Hi, there appears to be an issue that only affects users who have turned off Cleartype Font rendering within their Windows Settings. So a workaround for the moment would either be to turn Cleartype back on or disabling hardware acceleration in Firefox: https://support.mozilla.org/en-US/kb/performance-settings

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

Pkshadow said

Hi, there appears to be an issue that only affects users who have turned off Cleartype Font rendering within their Windows Settings. So a workaround for the moment would either be to turn Cleartype back on or disabling hardware acceleration in Firefox: https://support.mozilla.org/en-US/kb/performance-settings Please let us know if this solved your issue or if need further assistance.

Thanks once I figured out how to actually turn cleartype on in windows 10 it solved my issue. Thanks for the quick response and solution.

FWIW, for me the same issue was resolved by disabling uBlock Origin and enabling Adblock Plus.

Turning ClearType Font on and disabling hardware acceleration didn't fix it for me; it's disabling Fire Drag extension that fixed it. I ended up disabling all add-ons and re-enabling it back one by one to find out.

Hi cocoakitten, Pkshadow's post was marked as the solution by the person who asked the original question (mickeylearn). Your issue may have similar symptoms, but it is likely a different cause/solution. You should use https://support.mozilla.org/en-US/questions/new where volunteers can get more details about your setup.

Because this thread is solved and more people might start using it for their own questions, I'm going to lock it.