diff --git a/src/pocketmine/Player.php b/src/pocketmine/Player.php
index f9341c833..9f72b21c3 100644
--- a/src/pocketmine/Player.php
+++ b/src/pocketmine/Player.php
@@ -2011,6 +2011,7 @@ class Player extends Human implements CommandSender, InventoryHolder, IPlayer{
 					break;
 				}
 				$this->craftingType = 0;
+				$this->currentTransaction = null;
 				if(isset($this->windowIndex[$packet->windowid])){
 					$this->server->getPluginManager()->callEvent(new InventoryCloseEvent($this->windowIndex[$packet->windowid], $this));
 					$this->removeWindow($this->windowIndex[$packet->windowid]);
@@ -2046,13 +2047,13 @@ class Player extends Human implements CommandSender, InventoryHolder, IPlayer{
 				}
 
 
-				if($this->currentTransaction === null or $this->currentTransaction->getCreationTime() < (microtime(true) - 0.5)){
+				if($this->currentTransaction === null or $this->currentTransaction->getCreationTime() < (microtime(true) - 0.4)){
 					if($this->currentTransaction instanceof SimpleTransactionGroup){
 						foreach($this->currentTransaction->getInventories() as $inventory){
 							$inventory->sendContents($inventory->getViewers());
 						}
 					}
-					$this->currentTransaction = new SimpleTransactionGroup();
+					$this->currentTransaction = new SimpleTransactionGroup($this);
 				}
 
 				$this->currentTransaction->addTransaction($transaction);
@@ -2062,6 +2063,7 @@ class Player extends Human implements CommandSender, InventoryHolder, IPlayer{
 						$this->currentTransaction = null;
 						break;
 					}
+					console("tx#".spl_object_hash($this->currentTransaction)." EXECUTED");
 					foreach($this->currentTransaction->getTransactions() as $ts){
 						$inv = $ts->getInventory();
 						if($inv instanceof FurnaceInventory){
diff --git a/src/pocketmine/inventory/BaseInventory.php b/src/pocketmine/inventory/BaseInventory.php
index b5408bb29..21311c7e9 100644
--- a/src/pocketmine/inventory/BaseInventory.php
+++ b/src/pocketmine/inventory/BaseInventory.php
@@ -44,7 +44,7 @@ abstract class BaseInventory implements Inventory{
 	protected $title;
 	/** @var Item[] */
 	protected $slots = [];
-	/** @var \SplObjectStorage<Player> */
+	/** @var Player[] */
 	protected $viewers = [];
 	/** @var InventoryHolder */
 	protected $holder;
@@ -58,7 +58,6 @@ abstract class BaseInventory implements Inventory{
 	 */
 	public function __construct(InventoryHolder $holder, InventoryType $type, array $items = [], $overrideSize = null, $overrideTitle = null){
 		$this->holder = $holder;
-		$this->viewers = new \SplObjectStorage();
 
 		$this->type = $type;
 		if($overrideSize !== null){
@@ -121,12 +120,12 @@ abstract class BaseInventory implements Inventory{
 		}
 	}
 
-	public function setItem($index, Item $item){
+	public function setItem($index, Item $item, $source = null){
 		$item = clone $item;
 		if($index < 0 or $index >= $this->size){
 			return false;
 		}elseif($item->getID() === 0){
-			$this->clear($index);
+			$this->clear($index, $source);
 		}
 
 		$holder = $this->getHolder();
@@ -141,7 +140,7 @@ abstract class BaseInventory implements Inventory{
 
 		$old = $this->getItem($index);
 		$this->slots[$index] = clone $item;
-		$this->onSlotChange($index, $old);
+		$this->onSlotChange($index, $old, $source);
 
 		return true;
 	}
@@ -296,7 +295,7 @@ abstract class BaseInventory implements Inventory{
 		return $slots;
 	}
 
-	public function clear($index){
+	public function clear($index, $source = null){
 		if(isset($this->slots[$index])){
 			$item = Item::get(Item::AIR, null, 0);
 			$old = $this->slots[$index];
@@ -316,7 +315,7 @@ abstract class BaseInventory implements Inventory{
 				unset($this->slots[$index]);
 			}
 
-			$this->onSlotChange($index, $old);
+			$this->onSlotChange($index, $old, $source);
 		}
 
 		return true;
@@ -328,9 +327,12 @@ abstract class BaseInventory implements Inventory{
 		}
 	}
 
-	public function getViewers(){
+	public function getViewers($source = null){
 		$viewers = [];
 		foreach($this->viewers as $viewer){
+			if($viewer === $source){
+				continue;
+			}
 			$viewers[] = $viewer;
 		}
 
@@ -359,15 +361,15 @@ abstract class BaseInventory implements Inventory{
 	}
 
 	public function onOpen(Player $who){
-		$this->viewers->attach($who);
+		$this->viewers[spl_object_hash($who)] = $who;
 	}
 
 	public function onClose(Player $who){
-		$this->viewers->detach($who);
+		unset($this->viewers[spl_object_hash($who)]);
 	}
 
-	public function onSlotChange($index, $before){
-		$this->sendSlot($index, $this->getViewers());
+	public function onSlotChange($index, $before, $source = null){
+		$this->sendSlot($index, $this->getViewers($source));
 	}
 
 
diff --git a/src/pocketmine/inventory/BaseTransaction.php b/src/pocketmine/inventory/BaseTransaction.php
index e769a4d24..904132ffa 100644
--- a/src/pocketmine/inventory/BaseTransaction.php
+++ b/src/pocketmine/inventory/BaseTransaction.php
@@ -32,6 +32,8 @@ class BaseTransaction implements Transaction{
 	protected $sourceItem;
 	/** @var Item */
 	protected $targetItem;
+	/** @var float */
+	protected $creationTime;
 
 	/**
 	 * @param Inventory $inventory
@@ -44,6 +46,11 @@ class BaseTransaction implements Transaction{
 		$this->slot = (int) $slot;
 		$this->sourceItem = clone $sourceItem;
 		$this->targetItem = clone $targetItem;
+		$this->creationTime = microtime(true);
+	}
+
+	public function getCreationTime(){
+		return $this->creationTime;
 	}
 
 	public function getInventory(){
diff --git a/src/pocketmine/inventory/ChestInventory.php b/src/pocketmine/inventory/ChestInventory.php
index 3180d43e6..c5efeec72 100644
--- a/src/pocketmine/inventory/ChestInventory.php
+++ b/src/pocketmine/inventory/ChestInventory.php
@@ -53,8 +53,6 @@ class ChestInventory extends ContainerInventory{
 	}
 
 	public function onClose(Player $who){
-		parent::onClose($who);
-
 		if(count($this->getViewers()) === 1){
 			$pk = new TileEventPacket;
 			$pk->x = $this->getHolder()->getX();
@@ -64,5 +62,6 @@ class ChestInventory extends ContainerInventory{
 			$pk->case2 = 0;
 			Server::getInstance()->broadcastPacket($this->getHolder()->getLevel()->getPlayers(), $pk);
 		}
+		parent::onClose($who);
 	}
 }
\ No newline at end of file
diff --git a/src/pocketmine/inventory/ContainerInventory.php b/src/pocketmine/inventory/ContainerInventory.php
index 7dc092822..a9db23553 100644
--- a/src/pocketmine/inventory/ContainerInventory.php
+++ b/src/pocketmine/inventory/ContainerInventory.php
@@ -28,6 +28,7 @@ use pocketmine\math\Vector3;
 
 abstract class ContainerInventory extends BaseInventory{
 	public function onOpen(Player $who){
+		parent::onOpen($who);
 		$pk = new ContainerOpenPacket;
 		$pk->windowid = $who->getWindowId($this);
 		$pk->type = $this->getType()->getNetworkType();
@@ -49,5 +50,6 @@ abstract class ContainerInventory extends BaseInventory{
 		$pk = new ContainerClosePacket;
 		$pk->windowid = $who->getWindowId($this);
 		$who->dataPacket($pk);
+		parent::onClose($who);
 	}
 }
\ No newline at end of file
diff --git a/src/pocketmine/inventory/CraftingTransactionGroup.php b/src/pocketmine/inventory/CraftingTransactionGroup.php
index b90665ef1..14b7109f7 100644
--- a/src/pocketmine/inventory/CraftingTransactionGroup.php
+++ b/src/pocketmine/inventory/CraftingTransactionGroup.php
@@ -34,10 +34,11 @@ class CraftingTransactionGroup extends SimpleTransactionGroup{
 	/** @var Recipe */
 	protected $recipe = null;
 
-	public function __construct(TransactionGroup $group){
+	public function __construct(SimpleTransactionGroup $group){
 		parent::__construct();
 		$this->transactions = $group->getTransactions();
 		$this->inventories = $group->getInventories();
+		$this->source = $group->getSource();
 
 		$this->matchItems($this->output, $this->input);
 	}
@@ -97,7 +98,7 @@ class CraftingTransactionGroup extends SimpleTransactionGroup{
 		}
 
 		foreach($this->transactions as $transaction){
-			$transaction->getInventory()->setItem($transaction->getSlot(), $transaction->getTargetItem());
+			$transaction->getInventory()->setItem($transaction->getSlot(), $transaction->getTargetItem(), $this->getSource());
 		}
 		$this->hasExecuted = true;
 
diff --git a/src/pocketmine/inventory/DoubleChestInventory.php b/src/pocketmine/inventory/DoubleChestInventory.php
index b52765761..e56056336 100644
--- a/src/pocketmine/inventory/DoubleChestInventory.php
+++ b/src/pocketmine/inventory/DoubleChestInventory.php
@@ -50,12 +50,12 @@ class DoubleChestInventory extends ChestInventory implements InventoryHolder{
 		return $index < $this->left->getSize() ? $this->left->getItem($index) : $this->right->getItem($index - $this->right->getSize());
 	}
 
-	public function setItem($index, Item $item){
-		return $index < $this->left->getSize() ? $this->left->setItem($index, $item) : $this->right->setItem($index - $this->right->getSize(), $item);
+	public function setItem($index, Item $item, $source = null){
+		return $index < $this->left->getSize() ? $this->left->setItem($index, $item, $source) : $this->right->setItem($index - $this->right->getSize(), $item, $source);
 	}
 
-	public function clear($index){
-		return $index < $this->left->getSize() ? $this->left->clear($index) : $this->right->clear($index - $this->right->getSize());
+	public function clear($index, $source = null){
+		return $index < $this->left->getSize() ? $this->left->clear($index, $source) : $this->right->clear($index - $this->right->getSize(), $source);
 	}
 
 	public function getContents(){
diff --git a/src/pocketmine/inventory/Inventory.php b/src/pocketmine/inventory/Inventory.php
index 6bc3421d9..a61baae75 100644
--- a/src/pocketmine/inventory/Inventory.php
+++ b/src/pocketmine/inventory/Inventory.php
@@ -53,13 +53,15 @@ interface Inventory{
 	/**
 	 * Puts an Item in a slot.
 	 * If a plugin refuses the update or $index is invalid, it'll return false
+	 * If a source Player is specified, it won't send a Inventory update to it
 	 *
-	 * @param int  $index
-	 * @param Item $item
+	 * @param int    $index
+	 * @param Item   $item
+	 * @param Player $source
 	 *
 	 * @return bool
 	 */
-	public function setItem($index, Item $item);
+	public function setItem($index, Item $item, $source = null);
 
 	/**
 	 * Stores the given Items in the inventory. This will try to fill
@@ -160,11 +162,12 @@ interface Inventory{
 	/**
 	 * Will clear a specific slot
 	 *
-	 * @param int $index
+	 * @param int    $index
+	 * @param Player $source
 	 *
 	 * @return bool
 	 */
-	public function clear($index);
+	public function clear($index, $source = null);
 
 	/**
 	 * Clears all the slots
@@ -175,9 +178,11 @@ interface Inventory{
 	 * Gets all the Players viewing the inventory
 	 * Players will be viewing their inventory at all times, even when not open.
 	 *
+	 * @param Player $source
+	 *
 	 * @return Player[]
 	 */
-	public function getViewers();
+	public function getViewers($source = null);
 
 	/**
 	 * @return InventoryType
@@ -211,8 +216,9 @@ interface Inventory{
 	public function onClose(Player $who);
 
 	/**
-	 * @param int       $index
-	 * @param Item|null $before
+	 * @param int    $index
+	 * @param Item   $before
+	 * @param Player $source
 	 */
-	public function onSlotChange($index, $before);
+	public function onSlotChange($index, $before, $source = null);
 }
diff --git a/src/pocketmine/inventory/PlayerInventory.php b/src/pocketmine/inventory/PlayerInventory.php
index 0d40ca40c..1a831e439 100644
--- a/src/pocketmine/inventory/PlayerInventory.php
+++ b/src/pocketmine/inventory/PlayerInventory.php
@@ -144,7 +144,7 @@ class PlayerInventory extends BaseInventory{
 		}
 	}
 
-	public function onSlotChange($index, $before){
+	public function onSlotChange($index, $before, $source = null){
 		parent::onSlotChange($index, $before);
 
 		if($index >= $this->getSize()){
@@ -196,7 +196,7 @@ class PlayerInventory extends BaseInventory{
 		return $this->setItem($this->getSize(), $boots);
 	}
 
-	public function setItem($index, Item $item){
+	public function setItem($index, Item $item, $source = null){
 		if($index < 0 or $index >= $this->size){
 			return false;
 		}
@@ -211,15 +211,18 @@ class PlayerInventory extends BaseInventory{
 			}
 			$item = $ev->getNewItem();
 		}
-
-		$old = $this->getItem($index);
-		$this->slots[$index] = clone $item;
-		$this->onSlotChange($index, $old);
+		if($item->getID() === 0){
+			$this->clear($index, $source);
+		}else{
+			$old = $this->getItem($index);
+			$this->slots[$index] = clone $item;
+			$this->onSlotChange($index, $old, $source);
+		}
 
 		return true;
 	}
 
-	public function clear($index){
+	public function clear($index, $source = null){
 		if(isset($this->slots[$index])){
 			$item = Item::get(Item::AIR, null, 0);
 			$old = $this->slots[$index];
@@ -239,7 +242,7 @@ class PlayerInventory extends BaseInventory{
 				unset($this->slots[$index]);
 			}
 
-			$this->onSlotChange($index, $old);
+			$this->onSlotChange($index, $old, $source);
 		}
 	}
 
diff --git a/src/pocketmine/inventory/SimpleTransactionGroup.php b/src/pocketmine/inventory/SimpleTransactionGroup.php
index 60af227c4..9d6c85e54 100644
--- a/src/pocketmine/inventory/SimpleTransactionGroup.php
+++ b/src/pocketmine/inventory/SimpleTransactionGroup.php
@@ -23,6 +23,7 @@ namespace pocketmine\inventory;
 
 use pocketmine\event\inventory\InventoryTransactionEvent;
 use pocketmine\item\Item;
+use pocketmine\Player;
 use pocketmine\Server;
 
 /**
@@ -31,6 +32,8 @@ use pocketmine\Server;
 class SimpleTransactionGroup implements TransactionGroup{
 	private $creationTime;
 	protected $hasExecuted = false;
+	/** @var Player */
+	protected $source = null;
 
 	/** @var Inventory[] */
 	protected $inventories = [];
@@ -38,8 +41,19 @@ class SimpleTransactionGroup implements TransactionGroup{
 	/** @var Transaction[] */
 	protected $transactions = [];
 
-	public function __construct(){
+	/**
+	 * @param Player $source
+	 */
+	public function __construct(Player $source = null){
 		$this->creationTime = microtime(true);
+		$this->source = $source;
+	}
+
+	/**
+	 * @return Player
+	 */
+	public function getSource(){
+		return $this->source;
 	}
 
 	public function getCreationTime(){
@@ -55,6 +69,18 @@ class SimpleTransactionGroup implements TransactionGroup{
 	}
 
 	public function addTransaction(Transaction $transaction){
+		if(isset($this->transactions[spl_object_hash($transaction)])){
+			return;
+		}
+		foreach($this->transactions as $hash => $tx){
+			if($tx->getInventory() === $transaction->getInventory() and $tx->getSlot() === $transaction->getSlot()){
+				if($transaction->getCreationTime() >= $tx->getCreationTime()){
+					unset($this->transactions[$hash]);
+				}else{
+					return;
+				}
+			}
+		}
 		$this->transactions[spl_object_hash($transaction)] = $transaction;
 		$this->inventories[spl_object_hash($transaction->getInventory())] = $transaction->getInventory();
 	}
@@ -100,9 +126,6 @@ class SimpleTransactionGroup implements TransactionGroup{
 		$haveItems = [];
 		$needItems = [];
 		$this->matchItems($haveItems, $needItems);
-		$input = "";
-		$output = "";
-
 		return count($haveItems) === 0 and count($needItems) === 0 and count($this->transactions) > 0;
 	}
 
@@ -120,7 +143,7 @@ class SimpleTransactionGroup implements TransactionGroup{
 		}
 
 		foreach($this->transactions as $transaction){
-			$transaction->getInventory()->setItem($transaction->getSlot(), $transaction->getTargetItem());
+			$transaction->getInventory()->setItem($transaction->getSlot(), $transaction->getTargetItem(), $this->getSource());
 		}
 
 		$this->hasExecuted = true;
diff --git a/src/pocketmine/inventory/Transaction.php b/src/pocketmine/inventory/Transaction.php
index ca95a5f2a..edfe9acb9 100644
--- a/src/pocketmine/inventory/Transaction.php
+++ b/src/pocketmine/inventory/Transaction.php
@@ -44,4 +44,9 @@ interface Transaction{
 	 * @return Item
 	 */
 	public function getTargetItem();
+
+	/**
+	 * @return float
+	 */
+	public function getCreationTime();
 }
\ No newline at end of file