Like most everything in FL Studio (and Gol's creations), the ways to achieve what you want, might be different than most DAWs. So, it needs some time to learn. I'm still learning it and actually it is my second most used after Cubase. It is very different from Cubase, but I like it a lot really and I hope I can have enough time to use it.
I didn't spend a long time with FLStudio, but the notes can be moved easily with the arrow keys. There is the right click - delete thing, but one needs to remember to press E to select and P for pen (among others). Anyway, it is an advanced piano roll and very capable. It is really a pleasure to work with. So, for midi disco composition, I might use FL Studio while for the gloomy songs, Cubase is a better fit!
Love the stretch midi notes tool and the various other tools in the menu:
