Paper/nms-patches/ItemSign.patch

--- a/net/minecraft/server/ItemSign.java
+++ b/net/minecraft/server/ItemSign.java
@@ -4,6 +4,8 @@
 
 public class ItemSign extends ItemBlockWallable {
 
+    public static boolean openSign; // CraftBukkit
+    
     public ItemSign(Item.Info item_info) {
         super(Blocks.SIGN, Blocks.WALL_SIGN, item_info);
     }
@@ -12,7 +14,10 @@
         boolean flag = super.a(blockposition, world, entityhuman, itemstack, iblockdata);
 
         if (!world.isClientSide && !flag && entityhuman != null) {
-            entityhuman.openSign((TileEntitySign) world.getTileEntity(blockposition));
+            // CraftBukkit start - SPIGOT-4678
+            // entityhuman.openSign((TileEntitySign) world.getTileEntity(blockposition));
+            ItemSign.openSign = true;
+            // CraftBukkit end
         }
 
         return flag;