Hi, I'm that guy who specializes on Mac OS X related issues.
@Zungara, @illuminarti you can bring all windows of the app by either using Expose (usually assigned to F3) or by right clicking app's icon on the dock and selecting "Show All Windows" item. If window was managed to get out of screen (e.g. by attaching/detaching secondary displays) you should be able to bring it onscreen by selecting it in Expose view.
@Zungara, next time you encaunter the issue, please check that the window you're looking for is not listed under Dock->Cura->Show All Windows.