diff --git a/Source/OpenTK/Platform/MacOS/MacOSFactory.cs b/Source/OpenTK/Platform/MacOS/MacOSFactory.cs
index 9c79119b..43e7bd75 100644
--- a/Source/OpenTK/Platform/MacOS/MacOSFactory.cs
+++ b/Source/OpenTK/Platform/MacOS/MacOSFactory.cs
@@ -37,6 +37,9 @@ namespace OpenTK.Platform.MacOS
 
     class MacOSFactory : PlatformFactoryBase
     {
+        // Todo: we can query the exact amount via
+        // CGEventSourceGetPixelsPerLine. This is
+        // approximately 0.1f
         internal const float ScrollFactor = 0.1f;
         internal static bool ExclusiveFullscreen = false;