(If you want markers in piano-roll, then please explain further)
I agree, and so does many others, that it would be nice with some markers in SE, and down the line, this may be implemented. There are several ideas for this already.
The way i have done this, is to use one beat&bass-line for marking / song-structure
I describe the method, along with other ideas on structure, in a video series of 4:
https://www.youtube.com/watch?v=jMPH5prCMv4
Using a note in a block, will actualy create a tiiiny waste of performance, because all note event are processed, regardless of volume.
If you can make some graphic representation of things you would like to see, then it will be useful.
I have been thinking about transparent 'curtains' over song-editor, but inputs are most welcome
