Since updating Hummingbird Pro to Version 1.5.3 we've noticed that the site menu won't open (drop down) when view on an mobile device. Are you aware of an issues?
We're using an Elegant Themes theme called Divi (Version: 3.0.51) on the latest build of WP (4.8)
Because of this we've had to deactivate Hummingbird for the time being. Any advice you can offer would be appreciated.