I downloaded a few dreams with transitions, which work only once. That is if i set the dream it'll do a transition after which the image shrinks to a little point and doesn't reset.
For example: https://www.wincustomize.com/skins.aspx?skinid=1669&libid=50
which is a very nice dream, but after a few minutes it does a transition and leaves me with a little triangle.
Thinking it could be the designer, so i dl'd another:
which does the same but leaves me with a little square.
vista x64 ultimate sp2