web2py.validate_entropy in web2py.js is inside a closure, so cannot be accessed in web2py-bootstrap3.js. This is a bug -- the ajax_fields function was copied from web2py.js, and the reference to web2py.validate_entropy was left as is, even though the variable "web2py" is not defined in web2py-bootstrap3.js. You can fix it by changing:
web2py.validate_entropy($(this));
to:
$.web2py.validate_entropy($(this));
Note, this problem only arises if you add the IS_STRONG validator to db.auth_user.password.requires (which is not the default). In that case, the PasswordWidget in sqlhtml.py adds a "data-web2py_entropy", which triggers the call to the above line. The reason the menus don't work properly is because the above line breaks the Javascript code.
Anthony