I just successfully (mostly) edited a Theme using the Editor. Here are my challenges:
 
I was mostly working in the TRACK section --- CLIPS subsection --- making my audio clip backgrounds pastel colors with black foreground waveforms. When I select my custom theme with a new project it works fine. BUT, when I open an existing project the colors are all super wonky. Backgrounds and foregrounds are all off --- not like any theme I have. I thought if you change themes, any customization from old color adjustments shift to the new theme.  Is this a bug or am I buggy?
 
Thanks, and Happy New Year!

I'm not a theme editor, but I have wondered exactly how the theme options for these color preferences are affected by other settings in the Preferences window, for coloring of elements. Could there be some non-default options chosen ?
Also, any project where custom clip colors have been chosen... again, I don't know that the theme can override them. I think existing clips retain whatever color has been selected for them when they were instantiated, or "decorated" manually.

Thanks. I remember reading something in the manual or the online help or a thread about this issue but cannot recall the exact info. One of the editor experts will know...? :)

Yeah some times there are hangovers from the themes. I had it a few times. I thin it may be a confusion between the old color customization and the new theme editor

Okay, good to know. It's not a real problem as I can just revert to the theme used on those projects.