Can you pls share a link to the site as a private message here. There may be a JS error which is causing this. We need to take a closer look at the site to see why this is happening. Thanks.
Was unable to reproduce this in my machine. Pls let us know how to reproduce this. I did test your site in chrome, firefox and safari and no luck so far. Maybe some plugin is causing this? I see that you have installed many third party plugins, you can deactivate them one by one and see which one is causing the issue.