Not exactly sure what you mean with looping MIDI sequences. If you mean a way to repeat a MIDI pattern within a single sequence event just by dragging the sequence event larger, then the answer is no.
If you have a short phrase or beat that you want to repeat, you can create phantom sequence events. Phantom events refer to the same sequence, so edits performed on the sequence will be active on all the events referring to the sequence. You can create phantom events by starting a normal drag operation of a sequence event, and then holding the control key when dropping the event. The mouse cursor should show a ‘+’ symbol when control key is held.
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