Piano Roll Oversight

The piano roll is a significant tool within MuseScore that can drastically effect the way a piece of music sounds - if it was implemented properly. I recently decided to fiddle around with it and saw that I could both change the velocity and length values of the selected notes (as well as less commonly used "on time" value), which is typical for a piano roll. I find that a lot of the sounds I use along with the default MuseScore sounds have a very slight space between the notes when playing through a fast phrase for instance, giving off a very subtle staccato effect. So I used the piano roll to change the length of each note individually slightly (and this does not change the actual note value you placed, thankfully), and saw a far better improvement of the overall flow of sound.

However, it seems that the piano roll wasn't properly implemented, as being able to change the length or velocity or "on time" values of multiple notes at once (something all piano rolls are able to do) is impossible through it. Example, when selecting a single note through the piano roll, I can go and change its current value which is 1000, to 1200. But when I select multiple notes, the whole top area where I can change different values are all grayed out. This seems like a major oversight and I feel it could be a very easy fix.

Edit:
Here's an example of the difference. I showed this to an actual sax player and he said to split the difference to somewhere between 1100 and 1150 to make it sound even more realistic (he heard some very, very slight overlap now), but again I would have to edit the values of each note individually which is currently a very tedious task.

Version 1 (original) - https://drive.google.com/open?id=1PVf6TD8GNDs1dGcAXnDESHshmiLzrIAl
Version 2 (Piano Roll Edit) - https://drive.google.com/open?id=1bKWYEIYrJV-XI8wKLe4LcljZR2g8XgUM