How can I disable animations in Firefox when going full screen?

Question

I would like to disable the transition animation when I hit F11 to go full screen on Firefox.

The animation slowly pulls up all the tabs and bars off the screen instead of immediately hiding everything.

Answer 1

In the newest versions of Firefox:

1. Open the about:config website
2. Set toolkit.cosmeticAnimations.enabled to false

Tested on:

• Firefox 57.0b9 (32-bit) from the Debian experimental branch running on Debian testing (buster)
• Firefox 56.0 (64-bit) running on Ubuntu 17.10
• Firefox 68.0 (64-bit) running on FreeBSD 13.0-CURRENT

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References

• about:config browser.fullscreen.animateUp has no effect (support.mozilla.org)
• All the other the resources I found on the Internet were outdated (they suggest modifying options in about:config, which no longer exist).

Answer 2

Firefox 83.0:

1. Open the about:config
2. Change full-screen-api.transition-duration.enter from 200 200 to 0 0.
3. Change full-screen-api.transition-duration.leave from 200 200 to 0 0.