[Input] Allow extending JoystickDevice<>

diff --git a/Source/OpenTK/Input/JoystickDevice.cs b/Source/OpenTK/Input/JoystickDevice.cs
index 55a92be..8e239f5 100644 (file)
--- a/Source/OpenTK/Input/JoystickDevice.cs
+++ b/Source/OpenTK/Input/JoystickDevice.cs
@@ -155,7 +155,7 @@ namespace OpenTK.Input
     #region JoystickDevice<TDetail> : JoystickDevice
 
     // Provides platform-specific information about the relevant JoystickDevice.
-    internal sealed class JoystickDevice<TDetail> : JoystickDevice
+    internal class JoystickDevice<TDetail> : JoystickDevice
         where TDetail : new()
     {
         internal JoystickDevice(int id, int axes, int buttons)