[xwiki-users] Filter app livetable by checkbox value

Hi, Sorry in advance. I can't imagine that this hasn't been asked before but as I couldn't find anything I may have used the wrong key words. Anyway, my problem is: I have created an app with "App within minutes" on XWiki 7.4.3 and among others defined boolean fields (checkboxes). I also added them to the application livetable. The table displays, for example, "Yes" and "No" but filtering is not possible. If I enter "Yes" in the filter no rows are returned though documents matching this exist. So how can I filter for checkbox values in an app livetable? Regs, Dennis