Thank you all for you very useful suggestions.
I implemented everything you suggested, except for the subject-based shortcuts (for later maybe):
- Shortcuts F6 and Shift+F6: Switch to the next/previous page without overlap
- Custom shortcuts now include three options Simple/Full page/Extended. Full page automatically switches to the next page
- Events can be attributed to a specific channel
- Events can be represent as lines instead of dots
- Additional comments can be attached to each event
- Specific event categories can be hidden
This is all described in this tutorial:
https://neuroimage.usc.edu/brainstorm/Tutorials/EventMarkers#Hide_event_groups
Let me know if there are things that could be improved or that do not work as advertised.