It’s great that the Match PPQ Color Grid colors can be customized.
Unfortunately in my case any customization is reset to the default when Cubase is rebooted
The Match PPQ Color Grid dialog window does not include any preset saving options, though it appears that the Match PPQ Color Grid set up is saved within MIDI Editor presets.
When I save a MIDI Editor preset, my Match PPQ Color Grid remains available for new projects, provided Cubase is not rebooted.
As soon as Cubase is rebooted the Color Grid is reset to the default.