Lack of good accessibility labels on many of the UI controls that comprise MIDI editor window make it really difficult to make sense of the window's layout. In my particular case I am using VoiceOver screen reader on Mac OS 10.15 with Reaper 6.0.2..
I've put together a quick video screencast demonstrating the issue for anyone interested, especially Reaper developers!
https://drive.google.com/open?id=1xq...NdZkwNBGhuPDwV
Hope this helps.
Please let me know if I can provide more information to further demonstrate the issue and the difficulties involved.
Thanks for reading!
Victor