I've removed the Skin from my RadWindow since it doesn't fit the site (Skin=""), but it still seems to have the close button in there. Which is great - but currently it's totally invisible. Is there a way for me to customize the look of the close button somewhere?
I suppose you want to customize the look of the close button in the RadWindow with Skin="". You can achieve this by overriding the default CSS using !important as follows.