Menu dissapear after responsive menu is activated

Greetings
Great job on the theme

I tried to work on it but i encoutered the following error with most of your free themes.

Here is how you reproduce the problem:

1 Load: http://demo.zymphonies.com/free-theme/medical-zymphonies-theme/
2 Resize the browser in order to show the responsive menu.
3 Click on the resposive menu (but dont click on its links. just open and close the resp. menu)
4 Resize the browser back to desktop dimensions and there you go: the main menu is missing!

It must be a js thing but i counldnt figure it out