There are small previews when hovering over the app in the taskbar, so we can show a preview of each tab in each window.

Rob, can you update this bug with what you've discovered about the APIs and such?

Here's a link to ITaskBarList3 api. http://msdn.microsoft.com/en-us/library/dd391692(VS.85).aspx It wants native windows which wont' work as well in compositor land.

Ah, got mid-air'd. There's also a ITaskbarList4 interface (both are new in Windows 7): http://msdn.microsoft.com/en-us/library/dd562040(VS.85).aspx In particular, what we want is the RegisterTab and UnregisterTab functions (not the AddTab/DeleteTab calls...tabs is misleading for those) to be called for tab create/close. I'm not sure if we need to remove the main browser window but if we do, then a DeleteTab will be necessary. Each browser tab needs its own native child window - this is currently the case and not likely to change for a while according to roc. There is a particular message we need to wait for before we can make any calls on this interface - see the provided link for more details. This will require some widget changes. The COM bits will need to be in C++, but I'm not sure if it's a good idea to listen for new tabs in native code. Someone know knows more about the browser/xul should probably comment before we commit to a design. One important polish detail is that the tab bar is not changed when the preview happens. FWIW, IE8 doesn't redraw its tab bar. It might not be possible to know when a preview is happening. The API documentation has not improved since I last checked. Another polish detail that I'm not sure about is whether or not we can repaint while the user is previewing. It would be nice to redraw (checking for new mail messages for example) but perhaps that can be split out into another bug.

(In reply to comment #4) > One important polish detail is that the tab bar is not changed when the preview > happens. FWIW, IE8 doesn't redraw its tab bar. It might not be possible to know > when a preview is happening. The API documentation has not improved since I > last checked. > I'm really not much of a fan of this functionality in IE8. Viewing different content panes while the current foreground tab / tab title remains visible seems really weird to me. Not sure what's possible on our end but personally I'd like to see the tabs fade in and out along with the content. Maybe we could display the current active tab differently in it's thumbnail?

A 'glow' in the window border of the active tab's thumbnail would be slick. You could also glow its tab in the tab bar.

This is very similar to bug 474056. Taskbar thumbnails and previews are inseparable.