Slicer 4.8 used Qt 4.x and 4.10 uses Qt 5.x and there appears to be some debugging to do related to handling of various ‘retina’ and other multiresolution monitor support (the hardware and OS features are continuing to evolve, I’m sure). For example my recent mac build is completely screwed up with the latest Qt and macOS.
This will require some experimentation on the developer side, but also we’ll need a lot of people to test and provide feedback as we try different settings.