Created Unassigned: problem tab container en 1.5 version javascript runtime error: unable to get property 'length' of undefined or null reference i also get this same error on our website that has a tab container. [27820]

problem tab container en 1.5 version
unhandled exception at line 1, column 56851 in http://localhost:50192/samplesite/bundles/msajaxjs?v=c42ygb2u07n37m_sfa8zblgvu4rr2gsbo7mvuenjez81 0x800a138f -