Filter with multiple options

I have implemented the “new” feature for filtering data from dataset to a repeater; https://www.wix.com/corvid/example/filter-with-multiple-options

Working fine… However, on this page I only want to show the data that has a boolean item marked/true.

I have tried to set this filter in the dataset settings, but all items, including those with boolean not marked appears after a second or two…

It is probably something I need to put into the script I guess… but I am totally blank when it comes to coding… Can anybody please help me?

That makes use of the Selection Tags element on your page.
https://support.wix.com/en/article/adding-and-setting-up-selection-tags
https://www.wix.com/corvid/reference/$w.SelectionTags.html

Which as stated on the tutorial itself, makes use of the hasAll data query function to sort them.

dataQuery = dataQuery.hasAll(fieldToFilterByInCollection, selectedCategories); 

Are you using selection tags or something else like a checkbox as then you would need to use the checked option to know if it is true or false.