This is something that I found a couple of months ago, and wish I knew about it long time ago. The nice thing with looping in Logic is that you just drag in the upper right corner of the MIDI track to extend a region so it loops multiple times. The bad thing is that you usually want to turn the loop into a real midi track segment at some point, as you want to edit individual MIDI notes to make things more variated.
Well, Logic always had the menu option in the Region-Parameters called Turn Loops into Real Copies. And the default command shortcut is comand-option-control-L. So now it’s a breeze for me to just let it loop, and when I want to go in and start making a different kind of MIDI segment, use this to get me a copy of real MIDI notes. Bye-bye copy/paste of midi segments. Duh.