Carousel Has Broken Transitions

[robloo]

Describe the bug

I've seen it mentioned a few times and observed in the ControlCatalog transitions don't usually work for the Carousel control. I figure I should finally add an issue for this.

To Reproduce

1. Go to ControlCatalog
2. Click on Carousel
3. Swipe through the slides then change the transition types an keep swiping
4. See error

Expected behavior

Transitions should always be smooth.

Screenshots

Here is a really interesting one: The transition collection is "corrupted" to the point it has two transitions running at once. The most common failure mode is just to show nothing.

Desktop (please complete the following information):

• OS: Windows 10 Pro
• Version master@ 80803ee

Additional context

None

[robloo]

This was fixed by f0c89a6 in #9677