If you ever used the MIDI key editor or (piano roll) from Ableton Live, you will know what im talking about… You can with the arrow mouse just with a click paint a midi note, as you can do now with cubase 8.5, also in ableton live, you can delete midi notes with the same click/arrow, I mean no need different tools or buttons to do the task… You can use other tools of course but is simplified to one tool (if you want) something very similar in FL studio but with right click and left click…
About my second request… is a bit difficult to me to explain in english… I will try with a example:
I have a chord on where root key is C#
and I want to up this chord to E, Normally and the right way to do this is just to select all those midi notes and up to E in the midi editor
FL have an extra ability of keep your chord in C# in the midi editor, but the root key can be changed without moving the midi notes in the editor… Is just about select another root key (if you see the image attached in my first message you will understand better what im talking about) I find this very useful for some kind of things.