Hey Edwin,
Thanks for setting that up! Weel it looks like that the <header> has a higher z-index than the #main-content element which also has the overflow property set to hidden. All that said the snippet to fix this is:
#main-content{
overflow: visible!important;
z-index: 1000!important;
}
Add that code to your theme (or child theme stylesheet) or via Simple Custom CSS plugin and it should do the trick.
Please let me know if you need anything else,
Have a great weekend,
Nico