Hi Jo,
I believe you have uncovered a new bug! I thought that all you had to do is to make a new slider and rename it to have the name of the lost slider. But this doesn’t work. It should.
So, what you have to do is create a new slider and name it differently than the lost slider, say “age_filter” (with the underscore character). Now modify the formula (or formulas) that refer to “agefilter” to refer to “age_filter” instead.
Everything should be fine again.
Bill