Bug: stops my menu drop down

I’m running the Customizr theme. I really liked this plugin and was about to give it a good review. However, unfortunately when my Customizr theme is on an iPad/iPhone etc in responsive mode, having this plugin stops the menu dropping down more than once. That is, you click the menu & it drops down, you click the menu again & it drops up. But all further attempts to drop down the menu fail.

Any idea why this should behave like this?

https://www.ads-software.com/plugins/admin-in-english-with-switch/