Hello,
Please read this topic https://www.8theme.com/topic/search-in-fixed-menu/
Also for some reason when you first load the page it doesn’t show the search bar you have to scroll down then back up to see the search icon, is this because of the admin bar?
– do you have the same situation when a parent theme activated?
Also, you need to update required plugins – http://xstore.helpscoutdocs.com/article/37-plugins-update
Regards