Hi,
everything works fine now! First approach: downgrade of jquery -> problem fixed, 2nd approch: current jquery + replacing avia.js as described here: https://kriesi.at/support/topic/wordpress-4-5/#post-612181 -> problem fixed,

Thank you!

Thank you, it’s working fine! But not in the Quick CSS, only by using the file custom.css.
Kind regards,
Sonia

Sure, we only have problems when using enfold forms.