diff --git a/administrator/components/com_categories/models/fields/categoryedit.php b/administrator/components/com_categories/models/fields/categoryedit.php
index 36528f391895f..3864bc910e900 100644
--- a/administrator/components/com_categories/models/fields/categoryedit.php
+++ b/administrator/components/com_categories/models/fields/categoryedit.php
@@ -45,6 +45,7 @@ protected function getOptions()
 
 		// Let's get the id for the current item, either category or content item.
 		$jinput = JFactory::getApplication()->input;
+
 		// Load the category options for a given extension.
 
 		// For categories the old category is the category id or 0 for new category.
@@ -63,56 +64,57 @@ protected function getOptions()
 
 		$db = JFactory::getDbo();
 		$query = $db->getQuery(true)
-			->select('a.id AS value, a.title AS text, a.level, a.published')
-			->from('#__categories AS a')
-			->join('LEFT', $db->quoteName('#__categories') . ' AS b ON a.lft > b.lft AND a.rgt < b.rgt');
+			->select('DISTINCT a.id AS value, a.title AS text, a.level, a.published');
+		$subQuery = $db->getQuery(true)
+			->select('DISTINCT id,title,level,published,parent_id,extension,lft,rgt')
+			->from('#__categories');
 
 		// Filter by the extension type
 		if ($this->element['parent'] == true || $jinput->get('option') == 'com_categories')
 		{
-			$query->where('(a.extension = ' . $db->quote($extension) . ' OR a.parent_id = 0)');
+			$subQuery->where('(extension = ' . $db->quote($extension) . ' OR parent_id = 0)');
 		}
 		else
 		{
-			$query->where('(a.extension = ' . $db->quote($extension) . ')');
-		}
-		// If parent isn't explicitly stated but we are in com_categories assume we want parents
-		if ($oldCat != 0 && ($this->element['parent'] == true || $jinput->get('option') == 'com_categories'))
-		{
-			// Prevent parenting to children of this item.
-			// To rearrange parents and children move the children up, not the parents down.
-			$query->join('LEFT', $db->quoteName('#__categories') . ' AS p ON p.id = ' . (int) $oldCat)
-				->where('NOT(a.lft >= p.lft AND a.rgt <= p.rgt)');
-
-			$rowQuery = $db->getQuery(true);
-			$rowQuery->select('a.id AS value, a.title AS text, a.level, a.parent_id')
-				->from('#__categories AS a')
-				->where('a.id = ' . (int) $oldCat);
-			$db->setQuery($rowQuery);
-			$row = $db->loadObject();
+			$subQuery->where('(extension = ' . $db->quote($extension) . ')');
 		}
 
 		// Filter language
 		if (!empty($this->element['language']))
 		{
-
-			$query->where('a.language = ' . $db->quote($this->element['language']));
+			$subQuery->where('language = ' . $db->quote($this->element['language']));
 		}
 
 		// Filter on the published state
-
 		if (is_numeric($published))
 		{
-			$query->where('a.published = ' . (int) $published);
+			$subQuery->where('published = ' . (int) $published);
 		}
 		elseif (is_array($published))
 		{
 			JArrayHelper::toInteger($published);
-			$query->where('a.published IN (' . implode(',', $published) . ')');
+			$subQuery->where('published IN (' . implode(',', $published) . ')');
 		}
 
-		$query->group('a.id, a.title, a.level, a.lft, a.rgt, a.extension, a.parent_id, a.published')
-			->order('a.lft ASC');
+		$subQuery->order('lft ASC');
+		$query->from('(' . $subQuery->__toString() . ') AS a')
+			->join('LEFT', $db->quoteName('#__categories') . ' AS b ON a.lft > b.lft AND a.rgt < b.rgt');
+
+		// If parent isn't explicitly stated but we are in com_categories assume we want parents
+		if ($oldCat != 0 && ($this->element['parent'] == true || $jinput->get('option') == 'com_categories'))
+		{
+			// Prevent parenting to children of this item.
+			// To rearrange parents and children move the children up, not the parents down.
+			$query->join('LEFT', $db->quoteName('#__categories') . ' AS p ON p.id = ' . (int) $oldCat)
+				->where('NOT(a.lft >= p.lft AND a.rgt <= p.rgt)');
+
+			$rowQuery = $db->getQuery(true);
+			$rowQuery->select('a.id AS value, a.title AS text, a.level, a.parent_id')
+				->from('#__categories AS a')
+				->where('a.id = ' . (int) $oldCat);
+			$db->setQuery($rowQuery);
+			$row = $db->loadObject();
+		}
 
 		// Get the options.
 		$db->setQuery($query);
@@ -137,6 +139,7 @@ protected function getOptions()
 					$options[$i]->text = JText::_('JGLOBAL_ROOT_PARENT');
 				}
 			}
+
 			if ($options[$i]->published == 1)
 			{
 				$options[$i]->text = str_repeat('- ', $options[$i]->level) . $options[$i]->text;
@@ -179,10 +182,10 @@ protected function getOptions()
 						unset($options[$i]);
 					}
 				}
+
 				if ($user->authorise('core.edit.state', $extension . '.category.' . $oldCat) != true
 					&& (isset($oldParent))
-					&& $option->value != $oldParent
-				)
+					&& $option->value != $oldParent)
 				{
 					unset($options[$i]);
 				}
@@ -190,17 +193,16 @@ protected function getOptions()
 				// However, if you can edit.state you can also move this to another category for which you have
 				// create permission and you should also still be able to save in the current category.
 				if (($user->authorise('core.create', $extension . '.category.' . $option->value) != true)
-					&& ($option->value != $oldCat && !isset($oldParent))
-				)
+					&& ($option->value != $oldCat && !isset($oldParent)))
 				{
 					{
 						unset($options[$i]);
 					}
 				}
+
 				if (($user->authorise('core.create', $extension . '.category.' . $option->value) != true)
 					&& (isset($oldParent))
-					&& $option->value != $oldParent
-				)
+					&& $option->value != $oldParent)
 				{
 					{
 						unset($options[$i]);
@@ -208,10 +210,10 @@ protected function getOptions()
 				}
 			}
 		}
+
 		if (($this->element['parent'] == true || $jinput->get('option') == 'com_categories')
 			&& (isset($row) && !isset($options[0]))
-			&& isset($this->element['show_root'])
-		)
+			&& isset($this->element['show_root']))
 		{
 			if ($row->parent_id == '1')
 			{
@@ -219,6 +221,7 @@ protected function getOptions()
 				$parent->text = JText::_('JGLOBAL_ROOT_PARENT');
 				array_unshift($options, $parent);
 			}
+
 			array_unshift($options, JHtml::_('select.option', '0', JText::_('JGLOBAL_ROOT')));
 		}
 
diff --git a/libraries/joomla/user/user.php b/libraries/joomla/user/user.php
index bea0e420865be..b77ac5e9a6f12 100644
--- a/libraries/joomla/user/user.php
+++ b/libraries/joomla/user/user.php
@@ -388,12 +388,17 @@ public function getAuthorisedCategories($component, $action)
 		// Brute force method: get all published category rows for the component and check each one
 		// TODO: Modify the way permissions are stored in the db to allow for faster implementation and better scaling
 		$db = JFactory::getDbo();
+
+		$subQuery = $db->getQuery(true)
+			->select('id,asset_id')
+			->from('#__categories')
+			->where('extension = ' . $db->quote($component))
+			->where('published = 1');
+
 		$query = $db->getQuery(true)
 			->select('c.id AS id, a.name AS asset_name')
-			->from('#__categories AS c')
-			->join('INNER', '#__assets AS a ON c.asset_id = a.id')
-			->where('c.extension = ' . $db->quote($component))
-			->where('c.published = 1');
+			->from('(' . $subQuery->__toString() . ') AS c')
+			->join('INNER', '#__assets AS a ON c.asset_id = a.id');
 		$db->setQuery($query);
 		$allCategories = $db->loadObjectList('id');
 		$allowedCategories = array();