diff --git a/docs/en/reference/modeladmin.md b/docs/en/reference/modeladmin.md
index c708ab6f5..1a4457965 100644
--- a/docs/en/reference/modeladmin.md
+++ b/docs/en/reference/modeladmin.md
@@ -72,14 +72,17 @@ for the search form, override `[api:DataObject->getCustomSearchContext()]` on yo
 The results are shown in a tabular listing, powered by the `[GridField](/reference/grid-field)`,
 more specifically the `[api:GridFieldDataColumns]` component.
 It looks for a `[api:DataObject::$summary_fields]` static on your model class,
-where you can add or remove columns, or change their title.
+where you can add or remove columns. To change the title, use `[api:DataObject::$field_labels]`.
 
 	:::php
 	class Product extends DataObject {
 	   // ...
+	   static $field_labels = array(
+	      'Price' => 'Cost' // renames the column to "Cost"
+	   );
 	   static $summary_fields = array(
-	      'Name' => 'Name',
-	      'Price' => 'Cost', // renames the column to "Cost"
+	      'Name',
+	      'Price',
 	      // leaves out the 'ProductCode' field, removing the column
 	   );
 	}
diff --git a/model/ArrayList.php b/model/ArrayList.php
index 3496fe84c..cd05f06d8 100644
--- a/model/ArrayList.php
+++ b/model/ArrayList.php
@@ -19,7 +19,7 @@ class ArrayList extends ViewableData implements SS_List, SS_Filterable, SS_Sorta
 	 * @param array $items - an initial array to fill this object with
 	 */
 	public function __construct(array $items = array()) {
-		$this->items = array_values($items);
+		$this->items = $items;
 		parent::__construct();
 	}
 	
@@ -137,14 +137,9 @@ class ArrayList extends ViewableData implements SS_List, SS_Filterable, SS_Sorta
 	 * @param mixed $item 
 	 */
 	public function remove($item) {
-		$renumberKeys = false;
 		foreach ($this->items as $key => $value) {
-			if ($item === $value) {
-				$renumberKeys = true;
-				unset($this->items[$key]);
-			}
+			if ($item === $value) unset($this->items[$key]);
 		}
-		if($renumberKeys) $this->items = array_values($this->items);
 	}
 
 	/**
@@ -181,20 +176,16 @@ class ArrayList extends ViewableData implements SS_List, SS_Filterable, SS_Sorta
 	 */
 	public function removeDuplicates($field = 'ID') {
 		$seen = array();
-		$renumberKeys = false;
 
 		foreach ($this->items as $key => $item) {
 			$value = $this->extractValue($item, $field);
 
 			if (array_key_exists($value, $seen)) {
-				$renumberKeys = true;
 				unset($this->items[$key]);
 			}
 
 			$seen[$value] = true;
 		}
-
-		if($renumberKeys) $this->items = array_values($this->items);
 	}
 
 	/**
@@ -482,6 +473,7 @@ class ArrayList extends ViewableData implements SS_List, SS_Filterable, SS_Sorta
 			}
 		}
 
+		$itemsToKeep = array();
 
 		$hitsRequiredToRemove = count($removeUs);
 		$matches = array();
@@ -496,17 +488,13 @@ class ArrayList extends ViewableData implements SS_List, SS_Filterable, SS_Sorta
 		}
 
 		$keysToRemove = array_keys($matches,$hitsRequiredToRemove);
-
-		$itemsToKeep = array();
-		foreach($this->items as $key => $value) {
-			if(!in_array($key, $keysToRemove)) {
-				$itemsToKeep[] = $value;
-			}
-		}
-
 		// TODO 3.1: This currently mutates existing array
 		$list = /* clone */ $this;
-		$list->items = $itemsToKeep;
+
+		foreach($keysToRemove as $itemToRemoveIdx){
+			$list->remove($this->items[$itemToRemoveIdx]);
+		}
+
 		return $list;
 	}
 
diff --git a/model/Map.php b/model/Map.php
index d2cf4f456..c2d3a15cc 100644
--- a/model/Map.php
+++ b/model/Map.php
@@ -77,6 +77,8 @@ class SS_Map implements ArrayAccess, Countable, IteratorAggregate {
 		$oldItems = $this->firstItems;
 		$this->firstItems = array($key => $value);
 		if($oldItems) $this->firstItems = $this->firstItems + $oldItems;
+		
+		return $this;
 	}
 
 	// ArrayAccess
diff --git a/tests/model/ArrayListTest.php b/tests/model/ArrayListTest.php
index 0d568f05d..3087d2db0 100644
--- a/tests/model/ArrayListTest.php
+++ b/tests/model/ArrayListTest.php
@@ -443,15 +443,15 @@ class ArrayListTest extends SapphireTest {
 	 */
 	public function testSimpleExclude() {
 		$list = new ArrayList(array(
-			array('Name' => 'Steve'),
-			array('Name' => 'Bob'),
-			array('Name' => 'John')
+			0=>array('Name' => 'Steve'),
+			1=>array('Name' => 'Bob'),
+			2=>array('Name' => 'John')
 		));
 		
 		$list->exclude('Name', 'Bob');
 		$expected = array(
-			array('Name' => 'Steve'),
-			array('Name' => 'John')
+			0=>array('Name' => 'Steve'),
+			2=>array('Name' => 'John')
 		);
 		$this->assertEquals(2, $list->count());
 		$this->assertEquals($expected, $list->toArray(), 'List should not contain Bob');
@@ -481,12 +481,12 @@ class ArrayListTest extends SapphireTest {
 	 */
 	public function testSimpleExcludeWithArray() {
 		$list = new ArrayList(array(
-			array('Name' => 'Steve'),
-			array('Name' => 'Bob'),
-			array('Name' => 'John')
+			0=>array('Name' => 'Steve'),
+			1=>array('Name' => 'Bob'),
+			2=>array('Name' => 'John')
 		));
 		$list->exclude('Name', array('Steve','John'));
-		$expected = array(array('Name' => 'Bob'));
+		$expected = array(1=>array('Name' => 'Bob'));
 		$this->assertEquals(1, $list->count());
 		$this->assertEquals($expected, $list->toArray(), 'List should only contain Bob');
 	}
@@ -496,16 +496,16 @@ class ArrayListTest extends SapphireTest {
 	 */
 	public function testExcludeWithTwoArrays() {
 		$list = new ArrayList(array(
-			array('Name' => 'Bob' , 'Age' => 21),
-			array('Name' => 'Bob' , 'Age' => 32),
-			array('Name' => 'John', 'Age' => 21)
+			0=>array('Name' => 'Bob' , 'Age' => 21),
+			1=>array('Name' => 'Bob' , 'Age' => 32),
+			2=>array('Name' => 'John', 'Age' => 21)
 		));
 		
 		$list->exclude(array('Name' => 'Bob', 'Age' => 21));
 		
 		$expected = array(
-			array('Name' => 'Bob', 'Age' => 32),
-			array('Name' => 'John', 'Age' => 21)
+			1=>array('Name' => 'Bob', 'Age' => 32),
+			2=>array('Name' => 'John', 'Age' => 21)
 		);
 		
 		$this->assertEquals(2, $list->count());
@@ -517,23 +517,23 @@ class ArrayListTest extends SapphireTest {
 	 */
 	public function testMultipleExclude() {
 		$list = new ArrayList(array(
-			array('Name' => 'bob', 'Age' => 10),
-			array('Name' => 'phil', 'Age' => 11),
-			array('Name' => 'bob', 'Age' => 12),
-			array('Name' => 'phil', 'Age' => 12),
-			array('Name' => 'bob', 'Age' => 14),
-			array('Name' => 'phil', 'Age' => 14),
-			array('Name' => 'bob', 'Age' => 16),
-			array('Name' => 'phil', 'Age' => 16)
+			0 => array('Name' => 'bob', 'Age' => 10),
+			1 => array('Name' => 'phil', 'Age' => 11),
+			2 => array('Name' => 'bob', 'Age' => 12),
+			3 => array('Name' => 'phil', 'Age' => 12),
+			4 => array('Name' => 'bob', 'Age' => 14),
+			5 => array('Name' => 'phil', 'Age' => 14),
+			6 => array('Name' => 'bob', 'Age' => 16),
+			7 => array('Name' => 'phil', 'Age' => 16)
 		));
 
 		$list->exclude(array('Name'=>array('bob','phil'),'Age'=>array(10, 16)));
 		$expected = array(
-			array('Name' => 'phil', 'Age' => 11),
-			array('Name' => 'bob', 'Age' => 12),
-			array('Name' => 'phil', 'Age' => 12),
-			array('Name' => 'bob', 'Age' => 14),
-			array('Name' => 'phil', 'Age' => 14),
+			1 => array('Name' => 'phil', 'Age' => 11),
+			2 => array('Name' => 'bob', 'Age' => 12),
+			3 => array('Name' => 'phil', 'Age' => 12),
+			4 => array('Name' => 'bob', 'Age' => 14),
+			5 => array('Name' => 'phil', 'Age' => 14),
 		);
 		$this->assertEquals($expected, $list->toArray());
 	}
@@ -543,26 +543,26 @@ class ArrayListTest extends SapphireTest {
 	 */
 	public function testMultipleExcludeNoMatch() {
 		$list = new ArrayList(array(
-			array('Name' => 'bob', 'Age' => 10),
-			array('Name' => 'phil', 'Age' => 11),
-			array('Name' => 'bob', 'Age' => 12),
-			array('Name' => 'phil', 'Age' => 12),
-			array('Name' => 'bob', 'Age' => 14),
-			array('Name' => 'phil', 'Age' => 14),
-			array('Name' => 'bob', 'Age' => 16),
-			array('Name' => 'phil', 'Age' => 16)
+			0 => array('Name' => 'bob', 'Age' => 10),
+			1 => array('Name' => 'phil', 'Age' => 11),
+			2 => array('Name' => 'bob', 'Age' => 12),
+			3 => array('Name' => 'phil', 'Age' => 12),
+			4 => array('Name' => 'bob', 'Age' => 14),
+			5 => array('Name' => 'phil', 'Age' => 14),
+			6 => array('Name' => 'bob', 'Age' => 16),
+			7 => array('Name' => 'phil', 'Age' => 16)
 		));
 
 		$list->exclude(array('Name'=>array('bob','phil'),'Age'=>array(10, 16),'Bananas'=>true));
 		$expected = array(
-			array('Name' => 'bob', 'Age' => 10),
-			array('Name' => 'phil', 'Age' => 11),
-			array('Name' => 'bob', 'Age' => 12),
-			array('Name' => 'phil', 'Age' => 12),
-			array('Name' => 'bob', 'Age' => 14),
-			array('Name' => 'phil', 'Age' => 14),
-			array('Name' => 'bob', 'Age' => 16),
-			array('Name' => 'phil', 'Age' => 16)
+			0 => array('Name' => 'bob', 'Age' => 10),
+			1 => array('Name' => 'phil', 'Age' => 11),
+			2 => array('Name' => 'bob', 'Age' => 12),
+			3 => array('Name' => 'phil', 'Age' => 12),
+			4 => array('Name' => 'bob', 'Age' => 14),
+			5 => array('Name' => 'phil', 'Age' => 14),
+			6 => array('Name' => 'bob', 'Age' => 16),
+			7 => array('Name' => 'phil', 'Age' => 16)
 		);
 		$this->assertEquals($expected, $list->toArray());
 	}
@@ -572,29 +572,29 @@ class ArrayListTest extends SapphireTest {
 	 */
 	public function testMultipleExcludeThreeArguments() {
 		$list = new ArrayList(array(
-			array('Name' => 'bob', 'Age' => 10, 'HasBananas'=>false),
-			array('Name' => 'phil','Age' => 11, 'HasBananas'=>true),
-			array('Name' => 'bob', 'Age' => 12, 'HasBananas'=>true),
-			array('Name' => 'phil','Age' => 12, 'HasBananas'=>true),
-			array('Name' => 'bob', 'Age' => 14, 'HasBananas'=>false),
-			array('Name' => 'ann', 'Age' => 14, 'HasBananas'=>true),
-			array('Name' => 'phil','Age' => 14, 'HasBananas'=>false),
-			array('Name' => 'bob', 'Age' => 16, 'HasBananas'=>false),
-			array('Name' => 'phil','Age' => 16, 'HasBananas'=>true),
-			array('Name' => 'clair','Age' => 16, 'HasBananas'=>true)
+			0 => array('Name' => 'bob', 'Age' => 10, 'HasBananas'=>false),
+			1 => array('Name' => 'phil','Age' => 11, 'HasBananas'=>true),
+			2 => array('Name' => 'bob', 'Age' => 12, 'HasBananas'=>true),
+			3 => array('Name' => 'phil','Age' => 12, 'HasBananas'=>true),
+			4 => array('Name' => 'bob', 'Age' => 14, 'HasBananas'=>false),
+			4 => array('Name' => 'ann', 'Age' => 14, 'HasBananas'=>true),
+			5 => array('Name' => 'phil','Age' => 14, 'HasBananas'=>false),
+			6 => array('Name' => 'bob', 'Age' => 16, 'HasBananas'=>false),
+			7 => array('Name' => 'phil','Age' => 16, 'HasBananas'=>true),
+			8 => array('Name' => 'clair','Age' => 16, 'HasBananas'=>true)
 		));
 
 		$list->exclude(array('Name'=>array('bob','phil'),'Age'=>array(10, 16),'HasBananas'=>true));
 		$expected = array(
-			array('Name' => 'bob', 'Age' => 10, 'HasBananas'=>false),
-			array('Name' => 'phil','Age' => 11, 'HasBananas'=>true),
-			array('Name' => 'bob', 'Age' => 12, 'HasBananas'=>true),
-			array('Name' => 'phil','Age' => 12, 'HasBananas'=>true),
-			array('Name' => 'bob', 'Age' => 14, 'HasBananas'=>false),
-			array('Name' => 'ann', 'Age' => 14, 'HasBananas'=>true),
-			array('Name' => 'phil','Age' => 14, 'HasBananas'=>false),
-			array('Name' => 'bob', 'Age' => 16, 'HasBananas'=>false),
-			array('Name' => 'clair','Age' => 16, 'HasBananas'=>true)
+			0 => array('Name' => 'bob', 'Age' => 10, 'HasBananas'=>false),
+			1 => array('Name' => 'phil','Age' => 11, 'HasBananas'=>true),
+			2 => array('Name' => 'bob', 'Age' => 12, 'HasBananas'=>true),
+			3 => array('Name' => 'phil','Age' => 12, 'HasBananas'=>true),
+			4 => array('Name' => 'bob', 'Age' => 14, 'HasBananas'=>false),
+			4 => array('Name' => 'ann', 'Age' => 14, 'HasBananas'=>true),
+			5 => array('Name' => 'phil','Age' => 14, 'HasBananas'=>false),
+			6 => array('Name' => 'bob', 'Age' => 16, 'HasBananas'=>false),
+			8 => array('Name' => 'clair','Age' => 16, 'HasBananas'=>true)
 		);
 		$this->assertEquals($expected, $list->toArray());
 	}