Assegnate 3 su 5 stelle
I just tried Personas Plus 2.0.0 and it doesn't show the preview on FF56.0.2.
UPDATE: I have installed FF 57 in laptop and am using the updated PP but submitting and testing themes is very, very slow and time consuming. There needs to be a dismiss button to make it faster to go back to the previous theme. This is just my opinion so hopefully others will put their ideas in.