If the aboveThis argument is omitted then the command raises
window so that it is above all of its siblings in the stacking
order (it will not be obscured by any siblings and will obscure
any siblings that overlap it).
If aboveThis is specified then it must be the path name of
a window that is either a sibling of window or the descendant
of a sibling of window.
In this case the raise command will insert
window into the stacking order just above aboveThis
(or the ancestor of aboveThis that is a sibling of window);
this could end up either raising or lowering window.