Strange white bar in Visual Studio 2019

this is my first post here. I have this problem that appears only by using Visual Studio (both 2017 and 2019) when working with Unity (2018.3.12f1): there is basically a white column on the left and I don't know what it should be. I have no clue on how to remove it and it bothers me. It appeared when I installed the first time VS 2019, since then it appeared on the 2017 version too. I uninstalled both and tried again only with the 2017 version but it is still there. Does someone any way to remove that? Thanks in advance.

The colour of that element is set in Tools | Options | Environment | Fonts & Colors under the Text Editor category it is the background colour of "Indicator Margin".

In VS2019's (and VS2017's) dark theme it has a default value of RGB(51, 51, 51).

Maybe your setting is messed up?

PS. Many user settings (including this) are preserved in your profile including across re-installations and versions. These can be reset under Tools | Import or Export Settings.