How to change the color of the scroll bar of Visual Studio when it is in map mode? This is a picture of what seems to me now.

Basically, I just need to make transparent colors so that they blend in with the background. This was once part of the Powerivity Tools , and I remember you could change the colors in these settings. But in Visual Studio 2015, it was built into the IDE, and there are no obvious settings for colors.
I also use the Color Theme Editor extension, but if the color parameter is editable, I cannot find it.
I know that you can change these colors because I changed it earlier (my colors got reset recently). Does anyone know where these settings are?
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