How do I remove this movable grey and white circle from my S8?

[Android Central Question]

I have a grey and white circle on my S8, when you press it, it will show the recent apps shortcuts that are on the right side of the screen....I have tried to remove the recent apps shortcuts that come up From the right side of the screen and this appeared, and the now the shortcuts are still able to show up...I don't know how to fix this, as it is annoying and sometimes interferes with the ability to press icons on the phone! Help!!

 

[SpookDroid]

If you long press the circle, does an X appear? It's usually the app shortcut assistant or whatever it's called, but if you're using a 3rd party app that has a similar function, then that would complicate things unless you can tell which app that's coming from.