Fix dedicated server issue in some implementations of Block.getPickBlock. Closes #6566

src/main/java/net/minecraftforge/client/event/GuiScreenEvent.java

@@ -214,6 +214,7 @@ public class GuiScreenEvent extends Event
         }
     }
 
+    @Deprecated // Remove in 1.16
     public static class ActionPerformedEvent extends GuiScreenEvent
     {
         private Button button;