I'm in agreement with VideoTrack. I find it much easier to do tasks like this in the piano roll view than in the notation view.

Also note that in the piano roll view you can select a number of notes and lengthen or shorten all of them at once.

Whenever I get something stuck in the back of my throat, I dislodge it by drinking a beer.
It's called the Heineken Maneuver.

64 bit Win 10 Pro, the latest BiaB/RB, Roland Octa-Capture audio interface, a ton of software/hardware