In VS2010, what environment setting applies to mouse-over on region/sub collapse/expand?

I'm tweaking my environment settings and I've got all my colors happy except this one. When you hover over the "+" or "-" the entir开发者_StackOverflow中文版e affected area gets highlighted in white-ish color. This is annoying when you have a dark background like I have using Ragnarok Blue (or ZenBurn)

What Display Item is this so I can adjust?

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By going through each display item I discovered it's the "Collapsible Region" I suppose that should have been obvious.