Blender Git Loki

Fix T58904: Side tabs disappear when creating new View Layer

Using listener here, although I suspect we should be using message
subscriber only. That said, this mimics the behaviour of the buttons
main region.

As for the original bug report what was happening was that when
switching between viewlayers (or when creating one) we may not get the
same active object. So the context breadcrumbs are different.

And the bug itself was that we were missing a redraw on view layer
change.