How to hide or remove webpushr box from my users?

Hello!
I want to know How to hide or remove webpushr box from my website users?
I don’t want users to see webpushr box while editing their posts because I don’t need them to send many notifications for the same post.

screenshoot

Hi,

The box in the screenshot is not a Webpushr box, it is Onesignal’s. Please deactivate Onesignal plugin and hopefully their box will go away.