CB

When using Tabbed registration or profile edit and clicking the submit buttons it only does jQuery validation on the tab you're actively viewing. This is due to jQuery validator ignoring hidden inputs. This is good and bad as it stops it from validating inputs that aren't visible, but it also causes tabbed usages to be more or less broken for validation and reverting to PHP side validation only, which is less user friendly.

https://www.joomlapolis.com/forum/153-professional-member-support/225672-20b4-registration-feature-suggestion