How can I remove the rounded corners in Firefox?

Bonjour

A space for users to give product feedback https://support.mozilla.org/en-US/kb/what-mozilla-connect

A old discussion thread https://connect.mozilla.org/t5/discussions/hate-the-rounded-corners-inside-firefox-disabled-them-in-windows/td-p/110499 and a new discussion thread https://connect.mozilla.org/t5/discussions/take-project-nova-for-a-spin-in-nightly/td-p/131273

Thank you very much, this solution was helpful

If you mean the rounded corners around the browser window or tabs, I’d first check whether this appeared after a recent Firefox update. Some UI changes can’t be reverted through the normal settings, so it may depend on exactly which corners you mean. A screenshot would probably make it easier for someone here to point you to the right setting or workaround.

Setting browser.nova.enabled to false under about:config worked (on 157).

I hope that continues to make the necessary adjustments because the half rounded ends and circles is a poor UI usability choice IMO. Might work better on touch screens and maybe some prefer it aesthetically with the full rounding, but the delineation of the space enclosed is clearer with the greater internal clearance in the corners, and at least part of the edges straight to guide the eye (late 50's user with poor eyesight).

WARNING from the moderator team: Changing Firefox preferences from the about:config page can sometimes break Firefox or cause strange behavior. You should only do this if you know what you're doing. Please read Firefox advanced customization and configuration options to learn more.

I recommend that you do not use that preference as it is due to be removed in a future update.