Happened to read this:
https://www.mobileread.com/forums/sho...d.php?t=142033
I have many times done things to my Calibre and few clicks later decided I don't like it. Once I searched high and low how to get to the place where I changed 'Edit Metadata' screen - whole 5 minutes had passed from the change.
Wouldn't it be nice if there was 'undo' like in Word? Or ability to take 'snapshot' of settings, name it and save it (custom columns should be left alone of course). So I can save my settings, play to my heart's content and always return to the starting point (or other saved point).
Even textfile with settings would be helpful - then I can start from the top and one by one check what is different.