This is hard to explain, but I’ll try.
It’s because nothing changes when you glue 2 MIDI parts, MIDI is always shown as a “Part” in the project window (MIDI events are single notes). Any audio you record or drag and drop into the project will be a single loose “Event”, and these loose events will become a “Part” when glued together. In other words, they become a different thing.
A Part is a container for multiple Events.
Try enabling and disabling the Transparent Events preference and pay attention to your folder tracks and MIDI parts. You’ll notice that only the colored background of the “part” is removed, the “events” inside these parts do not change. The same happens to audio parts, only the background of the part itself is gone, the audio events inside the part do not change, and these events happen to be a solid block of color with a waveform displayed on top.
