Loading from a Multitrack Clip
When you load from a multitrack clip, the tracks from the selected multitrack clip are loaded from the bottom track to the top track. The last track is loaded as the background and subsequent tracks are loaded as matte and front pairs. This means that the last track is loaded as the common back clip, the second to last track is loaded as the matte clip of media 1, the third to last track is loaded as the front clip of media 1, the fourth to last track is the matte clip of media 2, and so on.
Gaps that are located at the start and end of a track are treated in two ways depending on which multitrack option you choose. If you select MultiTrack, each gap is filled with its preceding non-gap frame. If you select MultiTrack with Gap, each gap is filled with black frames.