Retain [Image] using [Image] does not work? -HELP

Hey guys,

I kinda have a problem with this block:

Clearing a piece out of an Image using a black image works perfectly, but retaining has no effect at all, why?
The code is the same, I just switched from "clear" to "retain".

I am using the newest public build.

I'm working with the same thing and everything works in my case.  Maybe post some more info about your test? (images used, actual code, whatever could help).