I have come across an interesting problem when using a 'Stealth Redirect' (also called URL masking) from my Domain server.
When using this redirect my domain gets redirected in a frame. This frame breaks the viewport and instead of the screen being the viewport the frame becomes the viewport. This problem accurs on ipads and other tablets.
The problem here is that when I use the redirect without the frame (no URL masking) my shadowbox centers nicely in the middle of the screen (using the viewport padding function). However when I use 'Steath redirect' and the frame becomes the viewport the shadowbox centers in the middle of the frame which is not nessecarely the center of the screen depending on where you are reading within the frame (the frame is higer than the screen height).