diff --git a/classes/Category.php b/classes/Category.php
index 06ba653a7..2800bf205 100644
--- a/classes/Category.php
+++ b/classes/Category.php
@@ -1233,6 +1233,17 @@ class CategoryCore extends ObjectModel
 			return false;
 		return ($this->nleft >= $interval['nleft'] && $this->nright <= $interval['nright']);
 	}
+	
+	public static function inShopStatic($id_category, Shop $shop = null)
+	{
+		if (!$shop || !is_object($shop))
+			$shop = Context::getContext()->shop;
+
+		if (!$interval = Category::getInterval($shop->getCategory()))
+			return false;
+		$row = Db::getInstance(_PS_USE_SQL_SLAVE_)->getRow('SELECT nleft, nright FROM `'._DB_PREFIX_.'category` WHERE id_category = '.(int)$id_category);
+		return ($row['nleft'] >= $interval['nleft'] && $row['nright'] <= $interval['nright']);
+	}
 
 	public function getChildrenWs()
 	{
diff --git a/classes/Product.php b/classes/Product.php
index 6279280d3..ef452762f 100644
--- a/classes/Product.php
+++ b/classes/Product.php
@@ -3978,18 +3978,19 @@ class ProductCore extends ObjectModel
 	{
 		if (!((int)$id_product > 0) || !is_array($categories) || empty($categories))
 			return false;
-		$sql = 'SELECT id_product FROM `'._DB_PREFIX_.'category_product` WHERE `id_product`='.(int)$id_product.' AND `id_category` IN(';
+		$sql = 'SELECT id_product FROM `'._DB_PREFIX_.'category_product` WHERE `id_product` = '.(int)$id_product.' AND `id_category` IN (';
 		foreach ($categories as $category)
 			$sql .= (int)$category['id_category'].',';
 		$sql = rtrim($sql, ',').')';
 
-		if (isset(self::$_incat[md5($sql)]))
-			return self::$_incat[md5($sql)];
-
-		if (!Db::getInstance(_PS_USE_SQL_SLAVE_)->executeS($sql))
-			return false;
-		self::$_incat[md5($sql)] = (Db::getInstance(_PS_USE_SQL_SLAVE_)->NumRows() > 0 ? true : false);
-		return self::$_incat[md5($sql)];
+		$hash = md5($sql);
+		if (!isset(self::$_incat[$hash]))
+		{
+			if (!Db::getInstance(_PS_USE_SQL_SLAVE_)->getValue($sql))
+				return false;
+			self::$_incat[$hash] = (Db::getInstance(_PS_USE_SQL_SLAVE_)->NumRows() > 0 ? true : false);
+		}
+		return self::$_incat[$hash];
 	}
 
 	public function getNoPackPrice()
diff --git a/modules/blockcategories/blockcategories.php b/modules/blockcategories/blockcategories.php
index 83c4e38da..3f1842ae1 100644
--- a/modules/blockcategories/blockcategories.php
+++ b/modules/blockcategories/blockcategories.php
@@ -203,7 +203,9 @@ class BlockCategories extends Module
 			}
 			if (Tools::isSubmit('id_product'))
 			{
-				if (!isset($this->context->cookie->last_visited_category) || !Product::idIsOnCategoryId($id_product, array('0' => array('id_category' => $this->context->cookie->last_visited_category))))
+				if (!isset($this->context->cookie->last_visited_category)
+					|| !Product::idIsOnCategoryId($id_product, array('0' => array('id_category' => $this->context->cookie->last_visited_category)))
+					|| !Category::inShopStatic($this->context->cookie->last_visited_category, $this->context->shop))
 				{
 					$product = new Product($id_product);
 					if (isset($product) && Validate::isLoadedObject($product))