Problem: The cursor shape is changed to indicate when it is behind an
unfocused floating window (since a2b92a5e). This behavior
cannot be controlled by a floating window that doesn't want
to dim the cursor.
Solution: Assign a zindex-offset of 50 to the zindex of the current
window. To not dim the cursor when creating a floating window
on top of the current window one can assign the zindex
accordingly.
5d3cda472c