I’d like to drag durations in the key editor without the risk of accidentally changing the pitch. It seems that using shift to constrain dragging is implemented elsewhere in Dorico, so I’d love to see this simple case addressed.
Or perhaps I’m missing something…
That’s weird, it should work. First drag the selection with the mouse and when it starts to move hold down SHIFT. Then it should allow you to move in whatever direction you’re moving the most.
That definitely doesn’t work for me.
Yes, I’m afraid in the piano roll editor this does not currently work – it’s implemented for the MIDI CC, tempo, pitch bend and dynamics editors, but not (yet) for the piano roll. We plan to address this in the next update, all being well.
Sorry, hadn’t realised it only worked for controllers… 
Thank you for the reply.