Gimp Portable Background Window

Hi all !
I'm new on this forum and I have one question.
I have installed Gimp Portable 2.6.6 and the 2 plugins "Background Windows" and "Photoshop Layout".
The second one is well working but the first one seems to do nothing: when I open two pictures, I have to tabs in the Windows taskbar...
Is there any other thing to do after the plugin installation ?
Thanks !!