Collapse Accordion transitions not working

[kokaruk]

Since v4.1 transitions are no longer working.

https://getbootstrap.com/docs/4.0/components/collapse/#accordion-example

Open / close events are smooth transition

https://getbootstrap.com/docs/4.1/components/collapse/#accordion-example

Open / close no animation transition is happening

[MartijnCuppens]

I can not reproduce this. What browser/OS are you using?

[patrickhlauke]

I will hazard a guess that this is related to prefers-reduced-motion ? #27525 (comment)

[kokaruk]

I can not reproduce this. What browser/OS are you using?
Safari, FF and Chrome on Mac
and FF and Chrome on Win 10

I will hazard a guess that this is related to prefers-reduced-motion ? #27525 (comment)
ah, yes. That exactly it.

So, its a feature, not a bug.
Is it reflected in the release notes somewhere so I can show it to the team?

Anyway, that resolves the issue.

[patrickhlauke]

Is it reflected in the release notes somewhere so I can show it to the team?

shiplist for 4.2.0 #26952 which lists, under CSS:

#27581: Add Sass variable for prefers-reduced-motion, add callout to affected components

In the docs, see the note in https://getbootstrap.com/docs/4.2/components/collapse/#how-it-works which points to https://getbootstrap.com/docs/4.2/getting-started/accessibility/#reduced-motion

[patrickhlauke]

and yes, the above are for 4.2.0, not 4.1.0 - the prefers-reduced-motion stuff was introduced earlier - see ship list for 4.1 #25375 which points to

#25641: Make use of prefers-reduced-motion media query.

but the ramifications / apparent side effects (for users whose system was set to prefer reduced motion, but weren't expecting that setting to apparently "break" carousels/collapses/etc) weren't that apparent at the time, which is why those notes/mentions only got shipped with 4.2.0