your shadowbox is really nice and I'm using it on http://ssmss.de But, after updating Firefox to 3.5 your shadowbox has got a bug.
When I try to open an external Site for instance 'Kontakt', the box appears, but before loading the page it looks normal, but after 0,5 sec the box is completly white and after that little moment my page is being shown.
Having tested your examples, it is not only a bug on my page but also on yours.
Please try to fix it ;)
Re: I want to give the main coder a tip (Firefox bug)
Unfortunately there's nothing that can be done about the white background. Setting the background color of the iframe (via background-color) does not have any effect and neither does changing the background color of the loading page (until it actually loads, of course). If anybody has another workaround for this, I'm all ears.
[[[ NOTE TO MICHAEL: Please update this in future releases. ]]]
This problem still exists in 3.0b. I tracked it down to the src value. Firefox intializes the IFRAME and it has a default background color of transparent. Therefore, the flash of white is seen because the default background of the containing page is a default white.
You CAN get around this. I've updated the shadowbox-iframe.js to correct this problem: