Problem with "align middle"

[Cyril SANTUNE <cyril santune gmail com>]

Hi guys,

When I use align top or bottom, I can "cheat" to align an object B
with an objet A without move the object A

For example, I want that A and B are align on top. But I don't want to
move A. So I move B under A to be sure only the object B move when I
use align top.

is there any way to do this with align middle ?
Can we "lock" an objet to forbid all move ? like an anchor ?


Sorry for my poor english.
Thank