Those Blue and Green blocks you see covering the bar numbers are Part Markers.

You can click on any bar number to insert one or change one or click again to change it back to none.

Blue = Substyle A

Green = Substyle B

Every Part Marker forces a Drum Fill in the preceding bar.

If you insert a Part Marker of the same color as the one preceding it, you will force only a Drum Fill in the previous bar with no Substyle change.


--Mac