MIDI events not showing in Project Window


In the main project window, all the midi tracks had midi events denoted by little blocks. They’re still there, but recently they’re almost greyed out on all but the selected track. If I select another track, that one shows proper ‘dark coloured’ midi events and the previous one reverts to the ‘can just about see them’ greyed-out colour.

I’ve been through all the options in ‘Preferences’ but for the life of me I can’t see what’s changed. Th only one that seems relevant is Preferences>Event Display>MIDI>Part Data Mode and that’s already set to the default ‘Blocks’.

Can anyone help?