Oops forgot this using statement.

Author: vchelaru

articles/tutorials/building_2d_games/21_customizing_gum_ui/snippets/optionsslider.cs

@@ -3,7 +3,7 @@
 using Gum.DataTypes.Variables;
 using Gum.Managers;
 using Microsoft.Xna.Framework;
-using MonoGameGum.Forms.Controls;
+using Gum.Forms.Controls;
 using MonoGameGum.GueDeriving;
 using MonoGameLibrary.Graphics;