Feature Request: picom-trans option to set opacity of under cursor window

[zen2]

I use picom with openbox and I use the mouse wheel to increase/decrease opacity of window when mouse cursor is on window title bar.

picom-trans can only set opacity of:

• current active window (-c)
• window designed by WINDOW_NAME (-n)
• window designed by WINDOW_ID (-w)
• window selected by next mouse click (-s)

I wish to have a new option to set opacity of under mouse cursor window to be able to change opacity of an inactive window because actually If i use the scroll wheel on an inactive window it change opacity of the current active window.
A new option -u for under mouse cursor window could be really handy.