martin rudalics <rudalics@gmx.at> writes:

>> But it seemed to work on the release branch.  Anyway, with your patches
>> I don't see the assertion violation any more so you should check them
>> in.
>
> Spoke to early.  Now setting the cursor in a C-l child frame doesn't
> work any more.

Back from the drawing board, please find now 3 patches attached.

Idea was right, only that something was missing: the selected frame is
insofar related to the update that if it is part of the z-order on the
root being updated, it determines which frame in the z-order has the
cursor. Sounds a bit complicated, but fixes the problem :-).

I have rebased to include a comment fix you mentioned in one of the old
commits.