Daiwa I was trying to figure out this situation. In turn I messed a lot up on my win10. LOL. Somehow I got it but but can't tell you how.
I will say this in case you wish to try it. In Windowblinds under settings. I have "Apply Windows accent color based on the current theme" Checked.
Where it says "Apply accent color to backgrounds (recommended)" I have that unchecked.
This may have nothing to do with what you are asking. I really never go into Windiowblinds and change anything except for a skin. I change my wallpaper, Windowblind and have WB, start10 and Old new explorer installed. This looks almost exactly like win7. At least as far as having Explorer, Startmenu and of course everything else WB changes.