diff --git a/src/util/RedBlackTree.hxx b/src/util/RedBlackTree.hxx
index 07012cede..2cffb156f 100644
--- a/src/util/RedBlackTree.hxx
+++ b/src/util/RedBlackTree.hxx
@@ -275,6 +275,8 @@ public:
 			auto &p = *parent;
 			const auto direction_in_parent = p.GetChildDirection(*this);
 
+			std::swap(color, successor.color);
+
 			successor.SetChild(Direction::LEFT, GetLeft());
 			SetChild(Direction::LEFT, nullptr);
 			SetChild(Direction::RIGHT, successor.GetRight());