Closable panel/container

I thought the alert message had a X button to close, but apparently not. Is there a container something similar to tabs, but vertical instead of horizontal?

I would also be interested in this sort of feature.

Maybe setting the tabs_location argument of your Tab to left or right would solve your problem? C.F. The refence documentation.

Moving tabs is easy, and as far as I know that is well documented, @ahuang11. The question I would also be interested in is a closable alter message