OnTopReplica is a tiny tool that displays a resizeable, always-on-top window to show you what's happening in another application.
Are you waiting for an internet TV show to start, for instance? Right-click in the OnTopReplica window, choose your browser or video player, and OnTopReplica will immediately display a duplicate of the video feed, that updates in real time. Resize it to suit your needs, move it to the side of the screen and then keep one eye on OnTopReplica while you get on with other things.
The program isn't just restricted to displaying full windows, either. If, say, your video player happens to be in the middle of a large web page, then you can tell OnTopReplica to duplicate a region, and just draw a rectangle around the video picture itself. The on-top window will then only display that specified region - everything else will be dropped.
It's a clever utility, and one that could be just as useful if you're looking to monitor some lengthy process, for instance - a bulky installation program, maybe, or the batch conversion of a folder full of videos. Don't waste your time regularly switching to the app you need to check, just let OnTopReplica display a thumbnail view of exactly what it's doing.