If you look at this demo, when clicking + on Main1, the border around the items in the group, and the group header, is growing with animation.
But when collapsing the group by clicking -, the stroke around the items and the header simply disappear, without doing it with animation.

According to the official developers, this is not a bug. (what?!)
Is it possible to override the closing animation somehow to make it work?

Btw, this is also affecting links. If you look at this demo (the bottom of the page), you can see that when closing the group, the link is jumping to the left of the group, instead of staying in place...

Thank you!