What are those bars and how can I turn them off?

[a.user_2]

So, I reinstalled on my new laptop, and I've used AE for a long time, so I'm pretty sure this shouldn't be here. Never showed up on my old laptop. Can someone tell me what this is ? It shows when I preview my project and then disappear quick. 

[Martin_Ritter]

This is not a feature, but looks like an issue with the gpu driver. Update or re-install it.

*Martin

[Mike_Abbott]

I've seen this happen with Windows (operating system) display scaling. Check this setting in Windows and see if setting it to 100% scaling solves the issue.