So, apparently there’s a work-around to access the self-study script, so I thought it’s better to have it in a dedicated topic.
@GrumpyPanda pointed me to another script that changes the pages of radicals, kanji and vocab called Self-Study Hide Info. Once you install it, you’ll see it on any page when you click on radicals, kanji or vocab from the menu.
There you’ll see a button which allows you to activate the old self-study script. Hope it helps.