Remove/Hide Change Tracking in 21.2

Hi there, 

I've just upgraded to 21.2 from a previous version and there's one or two interface things getting in the way and I'm not sure what to call them in order to search for how to turn them off. 

The main one is that there's now a bar along the left hand side of code view with colours in it dictating changes made or such? Basically when I click the side of a line or the line number to highlight/select that line for copying/deleting it's instead bringing up some old change that I don't want. How do I turn this off and what is this feature called? 

Here's a screenshot of the bar so you can see what I'm refering to! 

Any help would be appreciated, thanks!