From the perspective of attempting to get ideas onto paper before they evaporate, SP4 is IMHO much superior to Sibelius, Dorico, Staff Pad or even Kawai Touch Notation because, unlike those others, it successfully gets out of your way and lets you focus on the music rather than the process. That is high praise because it is so difficult to achieve the right balance between ergonomics, flexibility, transparency and power. Thank you for the obvious thought and care you have given to your efficient, consistent, and intuitive approach and implementation.
I would like to see more options for making a selection. Perhaps a persistent selection that can be modified by addition or deletion of subsequent selections. Something like this would not wander far from the current interface paradigm and would ameliorate the rigid limitiations of a rectangular selection region.
The best selection method I have seen is in Kawai Touch Notation, where any object or group of nearby objects can be selected with a freehand lassoo of any shape. This method is flexible, fast, and straightforward, totally intuitive. Quite a different interface paradigm than dragging a rectangle, and maybe too big a stretch away from SP4's current interface, but it sure is great to use. OTOH, pasting such a selection is not as obvious as pasting a rectangular selection - where should I paste it? Will it overwrite stuff? Etc.
I figured out a way to move notes from one voice/layer to another, but it is a cumbersome, tedious process. A one-tap menu command to do this would be awesome.
Eventually something like Filters in Sibelius would be great for quick, complex selections.
SP4 is a terrific app. Thank you.