Strange side bars on screen after Android 9

[TwinCam]

After updating to Android 9 some strange and irritating bars have appeared on both sides of the screen. They are located from the middle of the screen and one half of the remaining space downwards.

When I come to close (approximately two millimeters) this bars the keyboard locks up for 10+ seconds. When the keyboard is active this means that pressing the send button located at the right hand side in most apps will probably not work. I then have to minimize the keyboard to send the message.

If I slide the finger from a distance and closes in to this bars the touch is registrated. If I slide in from outside and in it seems like it is working like a 'back-button'.

This is not the normal edge menu. Is this some setting unintentionally set on?

Bars at each side of the screen

[BandOfBrothers]

Can you first try a soft reboot by turning the phone Off and On. 

If no joy then put the phone in Safe Mode which disables your downloaded apps and leaves the stock ones working to see if it's some app that's not playing nice with the update. 

[TwinCam]

The safe mode test was interesting. I now know that the base is is ok and this is caused by some app... Just need to find a way of detecting which ones is started automatically after boot... 

[BandOfBrothers]

Glad the Safe Mode option helped @TwinCam 

Just a case of deleting one app at a time and reboot until it disappears.

[TwinCam]

Oh joy! 

I opened the app list and made all running apps visible. 

By deactivating suspicious apps one by one I found an running app named 'one hand operation'. Disabling and then uninstalling this made trick. Thank you very much for guiding me in the correct direction  

[BandOfBrothers · Accepted solution]

You're very welcome @TwinCam