CSS Style Panel Disables

Something I have done to make the style panel only ‘flash’ brighten/then dim on selection of components of one particular page - does not do this on other or new pages in same project with the same .css file.

I can code view, comment out my custom .css, then uncomment, re-attach it and as long as I do not go back to the design tab, I can use it. BS4, FA pro, AppConnect Local.