I'm not sure what exactly is the problem. But, if I get it right you want to keep the windows from rescaling, right? If that's the case, just set the Fullscreen in Browser parameter on Configuration Settings to "Off".
Here's a screenshot to help you find the setting...
[attachment=0:1ze9xhgd][/attachment:1ze9xhgd]
Click on the project name on the top right and change the parameter on the left from Letterbox scale to Off.