diff --git a/Quik/Mouse.cs b/Quik/Mouse.cs
index b1f5871..c3c0865 100644
--- a/Quik/Mouse.cs
+++ b/Quik/Mouse.cs
@@ -2,7 +2,7 @@ using System;
 
 namespace Quik
 {
-    public enum MouseButton
+    public enum MouseButton : byte
     {
         Primary     = 1 << 0,
         Secondary   = 1 << 1,
@@ -11,7 +11,7 @@ namespace Quik
         Auxilliary2 = 1 << 4,
         Auxilliary3 = 1 << 5,
         Auxilliary4 = 1 << 6,
-        Auxilliary5 = 1 << 8,
+        Auxilliary5 = 1 << 7,
     }
 
     public struct MouseState