GROOVE LOCK™ - MIDI File Browsing
In addition to drag and drop, it’s also possible to click inside the Groove Lock™ field to open a file dialog, which allows browsing to any .MID file on your computer that you wish to import into the Arpeggiator.
NOTE: Omnisphere will only recognize the first 128 MIDI note events in a .MID file, so any subsequent notes are ignored.