How to change box highliter in Developer Edition?

Hi! Basic Firefox devtools highlight the box model filling content, padding, and margins. But it is not the case in Developer Edition:

Filled regions look more noticeable to me. May I ask for your help on how to make Developer Edition highlighter behave the same way?

Hi,

This changed in https://bugzilla.mozilla.org/show_bug.cgi?id=1734195

When prefers-reduced-motion is set to reduce, we now use simplified highlighters to avoid creating flashing effects on the screen which can be disturbing for some users.

Although I can imagine not everyone enabling prefer-reduced-motion had this issue so it makes sense to make this configurable.

Edit: Filed https://bugzilla.mozilla.org/show_bug.cgi?id=1817639

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Wow, so interesting! Thank you.

Indeed, in system preferences I turned on ā€œreduce motionā€ ā€” it is the only way to disable some distracting animations on macOS.

As I can see changing system preferences get the classic highlighter back (thank you again). But about:config -> prefers-reduced-motion -> 0 does not change browser behavior. Is it right? Shouldnā€™t the browser config ignore system settings in such case?

prefers-reduced-motion is not a preference supported by Firefox (at least I donā€™t thinks so) so updating that in about:config will not have any impact.

I think the only way here is for us to introduce a new preference which allows to override the default behavior.

Oh you could set ui.prefersReducedMotion to 0 instead

My Firefox has recently auto updated to 111 and Iā€™ve noticed this change immediately. I would like to revert this change, but setting ui.prefersReducedMotion to false in about:config does nothing. How can I restore the previous behaviour? The new highlighter is imho not a good change.

i just looked it up and Itā€™s not even defined in the about:config.

It seems that it is only used in test

did you try to set it to 0 (and not false), and restarted DevTools?

itā€™s used on the platform side to force the prefers reduced motion behavior.
Some prefs are not defined by default (e.g. donā€™t appear in about:config), but do have an effect when set

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Iā€™m not sure how to change the value from ā€œfalseā€ to ā€œ0ā€. I can only toggle the value between ā€œtrueā€ or ā€œfalseā€ by double clicking or using the toggle button, but Iā€™m unable to enter a custom value.

You need to remove the entry, and add a new one, choosing Number instead of the default Boolean

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Quick follow up:

We are going to disable those new highlighters by default, even if you have prefers-reduced-motion enabled. Instead there will be a setting in the DevTools settings panel where you can opt-in or out from this feature.

Work is happening in https://bugzilla.mozilla.org/show_bug.cgi?id=1817639, hopefully should land in Firefox 113.

Thank you for this thread, just spent 40 minutes googling to find this change, wondering if Iā€™m going crazy. I also have animations disabled in macOS for being distracting. The new highlighter is really hard to see.