I've configured the Task Manager to only display tasks from the current desktop. This works for every application except the Gimp, whose toolbox windows are shown in the task manager on every desktop. Is there some setting I could adjust to fix this?

I included a screenshot below that shows the following in order:
1. the current task manager settings
2. the task manager on desktop 2, where only gimp is open
3. the task manager on desktop 1, where only firefox is open

http://db.tt/RGqzqG22

Thanks

you could try the special window settings and specify that that particular window skips the taskbar
right click title bar of the toolbox window -> more actions -> special window settings -> arrangement and access ->

or use Gimp 2.8 single window mode