Disable full screen entirely

There isn’t a technological way to prevent any browser savvy person from loading an iframe full screen. I suppose the page could check if the document was full screen (or at least, the parent frame, regardless of the size of the browser window) and if so display alternate content. That’s about the closest you could come I think.

This isn’t implemented in GDE for now though – the toolbar options just control the toolbar. The closest thing to it is GDE will remove the full screen/new window button if you’re using the enhanced viewer at full screen, since it’s redundant.