diff --git a/classes/Category.php b/classes/Category.php
index 14976922f..35396a13b 100644
--- a/classes/Category.php
+++ b/classes/Category.php
@@ -1132,8 +1132,10 @@ class CategoryCore extends ObjectModel
 	 * @param mixed $id_category_parent
 	 * @return boolean true if succeed
 	 */
-	public static function cleanPositions($id_category_parent)
+	public static function cleanPositions($id_category_parent = null)
 	{
+		if ($id_category_parent === null)
+			return;
 		$return = true;
 
 		$id = Context::getContext()->shop->id;
diff --git a/classes/Product.php b/classes/Product.php
index a3192839d..442ce3df3 100644
--- a/classes/Product.php
+++ b/classes/Product.php
@@ -762,24 +762,15 @@ class ProductCore extends ObjectModel
 		if (empty($categories))
 			return false;
 
-		// take the first selected category to get the category tree (nleft and nright)
-		$category = new Category($categories[0]);
-		// get max position in each categories
-		$and = '';
-		if (Shop::isFeatureActive())
-			$and = '
-				AND (c.`nleft` < '.(int)$category->nleft.'
-				AND c.`nright` > '.(int)$category->nright.'
-				AND c.`level_depth` = 1)';
 		$result = Db::getInstance()->executeS('
 			SELECT c.`id_category`
 			FROM `'._DB_PREFIX_.'category_product` cp
 			LEFT JOIN `'._DB_PREFIX_.'category` c
 				ON (c.`id_category` = cp.`id_category`)
 			WHERE cp.`id_category` NOT IN('.implode(',', array_map('intval', $categories)).')
-				'.$and.'
-				AND cp.id_product = '.$this->id
+			AND cp.id_product = '.$this->id
 		);
+
 		foreach ($result as $categ_to_delete)
 			$this->deleteCategory($categ_to_delete['id_category']);
 		// if none are found, it's an error
diff --git a/controllers/admin/AdminCategoriesController.php b/controllers/admin/AdminCategoriesController.php
index 0acbb57b0..cfabea6e7 100644
--- a/controllers/admin/AdminCategoriesController.php
+++ b/controllers/admin/AdminCategoriesController.php
@@ -530,7 +530,8 @@ class AdminCategoriesControllerCore extends AdminController
 		foreach (Tools::getValue($this->table.'Box') as $id_category)
 		{
 			$category = new Category((int)$id_category);
-			$cats_ids[$category->id] = $category->id_parent;
+			if (!$category->isRootCategoryForAShop())
+				$cats_ids[$category->id] = $category->id_parent;
 		}
 		
 		if (parent::processBulkDelete())
@@ -546,13 +547,13 @@ class AdminCategoriesControllerCore extends AdminController
 	
 	public function processDelete()
 	{
+		$category = $this->loadObject();
 		if ($this->tabAccess['delete'] === '1')
 		{
-			if ($this->isRootCategoryForAShop())
+			if ($category->isRootCategoryForAShop())
 				$this->errors[] = Tools::displayError('You cannot remove this category because a shop uses this category as a root category.');
 			else if (parent::processDelete())
 			{
-				$category = $this->loadObject();
 				$this->setDeleteMode();
 				$this->processFatherlessProducts((int)$category->id_parent);
 				return true;
@@ -574,7 +575,6 @@ class AdminCategoriesControllerCore extends AdminController
 		/* Delete or link products which were not in others categories */
 		$fatherless_products = new Collection('Product', Context::getContext()->language->id);
 		$fatherless_products->where('id_product', 'notin', $all_product_asso);
-		
 		foreach ($fatherless_products as $poor_product)
 		{
 			if (Validate::isLoadedObject($poor_product))
@@ -585,19 +585,12 @@ class AdminCategoriesControllerCore extends AdminController
 				{
 					if ($this->disable_products)
 						$poor_product->active = 0;
-					$poor_product->addToCategories($id_parent);
+					$poor_product->id_category_default = (int)$id_parent;
+					$poor_product->addToCategories((int)$id_parent);
 					$poor_product->save();
 				}
 			}
 		}
-
-		/* Set category default to Home category where categorie no more exists */
-		Db::getInstance()->execute('
-			UPDATE `'._DB_PREFIX_.'product_shop`
-			SET `id_category_default` = '.(int)Configuration::get('PS_HOME_CATEGORY').'
-			WHERE `id_category_default`
-			NOT IN (SELECT `id_category` FROM `'._DB_PREFIX_.'category`)
-		');
 	}
 
 	public function processPosition()