Loop/repeat Midi In Pro Tools? Options

[meadows.83]

i'm using pro tools le 6.2.2 on panther, and i want to be able to just do my midi(strings) on my keyboard once, over my drum beat, and then repeat the beat and midi, but when i try to do it, certain notes get cut off of the midi info. Is there a correct way to do this? I even tried to turn midi from notes to a region, but still can't do it. thanks for the help.