You need to open up Skinstudio. File-> Open current Windowblinds Skin -> Click on "Change skin colours" tab-> Drop down menu, select "Show me the skin defined system colours" ->Look for Explorer background (Win10)->click on it-> Click on "Change colour"->Color selection popup. Pick your color->click "OK"-> Click "Apply" -> click "OK" to save. Open up explorer. If the color do not apply. Try restart Explorer.exe.

Thank you,
Basj,
Stardock Community Assistant