This is a followup to my Friday Fun: Select Records / Checkboxes with Scrollbars post from last Friday. It seems I'm unable to attach files to the original post there or even to comments.
Anyway,here's a PDF description and two sample files.
Checkbox Record Selector minimum.fmp12 is the file in the video demo.
Checkbox Record Selector.fmp12 uses proper database conventions like key fields.
and here's the original demo video (embedded from the original post) for anyone who has just stumbled across this without having seen the original post: