[feature request] Sticky Replica

[VastLaugh]

The ability to anchor. or stick, a replica onto the window of any program. The replica would tag along whenever that window is moved around. It could be anchored over a window or stuck onto the side of a window's border.
If the window's size becomes smaller than the replica's size, the replica detaches.
I will refrain from speculating what its behavior should be when the window gets minimized.