CatServer/patches/net/minecraft/item/ItemLead.java.patch

--- ../src-base/minecraft/net/minecraft/item/ItemLead.java
+++ ../src-work/minecraft/net/minecraft/item/ItemLead.java
@@ -1,5 +1,7 @@
 package net.minecraft.item;
 
+import org.bukkit.event.hanging.HangingPlaceEvent;
+
 import net.minecraft.block.Block;
 import net.minecraft.block.BlockFence;
 import net.minecraft.creativetab.CreativeTabs;
@@ -54,9 +56,24 @@
             {
                 if (entityleashknot == null)
                 {
+                    // CraftBukkit start - fire HangingPlaceEvent
                     entityleashknot = EntityLeashKnot.createKnot(worldIn, fence);
+                    HangingPlaceEvent event = new HangingPlaceEvent((org.bukkit.entity.Hanging) entityleashknot.getBukkitEntity(), player != null ? (org.bukkit.entity.Player) player.getBukkitEntity() : null, worldIn.getWorld().getBlockAt(i, j, k), org.bukkit.block.BlockFace.SELF);
+                    worldIn.getServer().getPluginManager().callEvent(event);
+
+                    if (event.isCancelled()) {
+                        entityleashknot.setDead();
+                        return false;
+                    }
+                    // CraftBukkit end
                 }
 
+                // CraftBukkit start
+                if (org.bukkit.craftbukkit.event.CraftEventFactory.callPlayerLeashEntityEvent(entityliving, entityleashknot, player).isCancelled()) {
+                    continue;
+                }
+                // CraftBukkit end
+                
                 entityliving.setLeashedToEntity(entityleashknot, true);
                 flag = true;
             }