I wondered if this functionality was built in or if it is even scriptable.
In Gimp's new single window mode, it still treats the main canvas and the Layers dock as 2 separate windows that steal focus from each other. This isn't a problem in multi window mode even though my window manager is set to "Click to Focus"
I wondered if this could be automated to use "Focus Follows Mouse", but only for Gimp windows.
xubuntu 12.04-LTS (no unity) Gimp 2.8.2