I had a problem with that. It wasn't too bad since it didnt take THAT long but it was enough of an issue for me to return it. I figure that if I'm going to buy an homescreen app, I want it to be as flawless as possible (except for the occasional but rare glitches).
I eventually switched to Launcher+, which has been okay so far.
I used to have a problem with redrawing icons and widgets but in the dxTop settings at the bottom I checked the Persistant Mode box and it solved the issue.