Why won't it randomize?

I have clouds that I want to exit the layout and then move back to the other side of the layout, resize themselves and move back in to the layout.

The movement is working fine, but the clouds are always their original size when they come back in. Why?? <img src="smileys/smiley5.gif" border="0" align="middle" />

Here's the code:

<img src="https://dl.dropbox.com/u/10196246/cloud1.JPG" border="0" />

Got this sorted by changing the "Is outside layout" to an on collision event with a crude object off screen. For some reason that does it.