Flex container does not hide via dynamic attribute

I have a page in which I have a number of forms which show/hide on button click which toggles a variable tied to the show event of the element (mainly to show insert form below table). Setting dynamic show/hide events for forms and containers works perfectly however when applied to a flex container the container will not hide.

Here is a quick mini example
http://dev.findmystudentdigs.co.uk/toggleflex.html

Is this a bug or a bootstrap limitation?