Blank option in the nav-bar

[cyber-exon]

Sir, Your plugin is installed in my blogger theme and it's great. But someday ago I found some issue in it. When you open up the nav-bar in the mobile version of the site, it shows a blank option. I want to remove it, please help me out.

I am leaving the address of my blog site. The top menu is having that problem in the mobile view of the site. www.programmics.in

Regards,
Prateek Singh.