Change screen background color without any defer

[michenglaoxu]

I would like to change the screen background color using the Framed color box.  I can do this using property node. The problem is I cannot update the screen simultaneously as that in VI edit mode. I hope the screen background color can update as the mouse moving on the framed color box.   Does anyone know a solution? Thanks.

[falkpl]

Here is an OK cheat.  Dont use a background, make the color box larger than the screen and move to the back most element.  Looks the same but isnt perfect. 

Paul