ofxFenster, how to render at 0,0 with setBorder set to false???

Hi guys I am posting here because this is starting to do my head in. When rendering to a 2nd screen with ofxFenster I am asking it to render at pos 0,0 with the following command to turn off the window border.

  
imgFenster->setBorder(false);  

This renders me a window with the border off but ends up rendering at something like 0,10 instead of 0,0. This is fine if you want to render in fullscreen mode but I am doing a set this weekend on an LED wall with a tiny res (288,160) so that 10 pixels or so I am loosing turns out to scale up to be a big problem.

I’ve tried subtracting 10 pixels from 0 but this doesn’t work. Has anyone had any success in getting round this annoying bug? Thanks.