Move Drag Between Outputs - Alpha Adjustment/Animation Feature Request

[soreau]

Some environments that support multiple monitors behave in the same way as Wayfire, but there is a nice feature, notable on ChromeOS. When dragging a surface from one output to another, the output on which it will remain stays 100% alpha, while the side(s) of the surface on the output on which it will not be shown drops to 50%. Animate the transition would be another touch above.