diff --git a/src/ribbon/art_msw.cpp b/src/ribbon/art_msw.cpp
index 4041079aeb..ad494d5863 100644
--- a/src/ribbon/art_msw.cpp
+++ b/src/ribbon/art_msw.cpp
@@ -144,7 +144,7 @@ void wxRibbonMSWArtProvider::SetColourScheme(
 
     // Map primary saturation from [0, 1] to [.25, .75]
     bool primary_is_gray = false;
-    const float gray_saturation_threshold = 0.01;
+    static const double gray_saturation_threshold = 0.01;
     if(primary_hsl.saturation <= gray_saturation_threshold)
         primary_is_gray = true;
     else