I’m just curious, is there a specific reason for reproducing 3D Slicer’s appearance instead of building your application on that platform? The main advantage would be that the feature you described is already implemented and works well, and in case you find any issues then you can report it and others fix it for you for free. This way you can spend your time with implementing features that sets your application apart from others, not waste years with redeveloping all the features that every other medical imaging applications already have.