Image: How can I hide the posting button for certain permissions

I am using Mayro theme and there's a nice floating button on the bottom right for asking a new question. 

In the admin?permissions, I have set the permission for asking questions to "experts" and this hides the "Ask a question" link from the nav menu for users without the ability to post questions, which is fine.

(See image below)

But the "Ask a question" button still floats on the bottom right even for other users. I want to also hide it from there just as it is hidden on the navigation menu based on the permissions and levels.

Note that the "Ask a question" has been translated to "Add post" but it's the same.