I have a request I’d like you to consider. A Select/Drag/Copy function. You have the first two, which I frequently use. Now add Alt Select/Drag, which would make a copy of the select note/object and copy it to another location. And don’t restrict to the notes selected to the pitches. That is if I have a series where each return on the series is a third higher, I can simply drag the note to the location. This would be very cool and helpful.
Thank you
Use alt-click to do this (multiple times if needed). Make a selection then alt-click somewhere else to paste it.
From the Version History of Dorico 5.0.20 about Live note editing
“We have added constraints so that you can be sure you are editing either the pitch or the duration, but never both, and there is strong visual feedback in the score to ensure that you are always aware when you are editing the music.”
And a video:
Although you can copy-drag and repitch notes in the same move in the Key Editor.
It works. 
Thank you all for your guidance.