Is there anyway to specify that the background is grey or something?

In Windows Control Panel? Emplode just uses the standard system colour AFAIR. This is IMO the Right Thing, as you only have to fix it once for it to affect any application with a maximised window.

Having said that, I'm not actually near a Windows machine to check whether it works -- if there isn't anything you can change in Control Panel to change Emplode's colouring, that's a bug.

Peter