Simple glitch: When maximizing, any block on the Song Editor that goes past the window's previous size will not be rendered. The window can be updated by simply moving a track to another place, though.
1. Have several instruments and blocks of notes on the Song Editor.
2. Shrink the Song Editor to the smallest size possible.
4. If you can't notice any missing note blocks, just focus your eyes on a blank spot, move a track out of place, and you should spot the missing blocks pop up into view.