The compositor tries to switch to the next tabbox client when currently
highlighted client is closed. Though there is a small issue with that.
Because the switch happens too late, a dangling pointer can be inserted
into the unconstrained stacking order, which can lead to a crash later on.
There are two cases:
- compositing is on;
- compositing is off.
Compositing is on: TabBox will try to un-elevate currently highlighted
client, though by that time the client no longer owns EffectWindow, so
this is basically a no-op (that's why we haven't experienced this bug
Compositing is off: TabBox will try to restack currently hightlighted
client under the next tabbox client. Given that the restack method
doesn't do any sanity checks(see Client::manage why), a client that is
about to be destroyed will be re-inserted back into the unconstrained
This change ensures that the switch happens before currently highlighted
client is removed from the stacking order.