[JKT]

When the Tabs first came about in the 5.0 sneaky peeks, this was one of my first feature requests... however, speaking from experience, this isn't one of my desired features any more. There's a Firefox extension (only works up to version 1.5.x) that does this and it is actually a lot less helpful than you would think, rather than more helpful. It is simply much more difficult to recognise the content of the tab when it doesn't include the identifying information that you get at the top of pages (e.g. when you have scrolled a long thread in a forum)*. Also, it is quite visually distracting to have both the main window content and the tab content alter at the same or similar times (although this could have been the implementation - the tab updated once you finished scrolling and there was an ever so slight lag between the update and the time you stopped scrolling). If OmniGroup did implement this, then their method of doing so would have to avoid this visual distraction.

Edit: * where this might not be a problem is when you use very large tabs by resizing the drawer so that you can just about read the content in the thumbnail.