confirmed with svn on Gentoo/IntelP2. the same with
unhiding. it also takes 100% CPU when moving the path inside
the Download button, or its offset.
as a workaround, make a bitmap out of the button. especially
try to avoid text-to-path actions, as they create a lot of
nodes. this is no excuse for inkscape's behaviour, however,
because with 200 nodes, this should not show.