This happens to me as well. The part of the interface which is essentially the windows boarders (in particular, at the top) with the controls that that let you close a window (the "x" button in the upper right) are invisible. I can guess and click to the right of the window title and finally hit something that either centers the window on the screen or closes the window altogether (the latter behavior is the desired behavior). I am running a Mac with osx 10.7.5 and KSP 0.23. This add-on to ksp is excellent so am hoping it can be "repaired" to work properly for us Mac folks. Thanks Romfarer!!!
