Today I played a little bit with high resolution and things seem to work fine. For our OverlayMBS class, you need to provide picture and mask with higher resolution. But as you see in this example, it has an effect:
Left the low res, right the high res version of the same app.
If you want to test, compile your app to Cocoa and add the NSHighResolutionCapable key to the info.plist with boolean YES value. Running the app in high res mode works in general, but there is a lot to fix if needed. In our 12.3pr plugins, we have a window.BackingScaleFactorMBS function so you know when to use high res back buffer for canvas drawing.