diff --git a/src/Symfony/Component/Form/Extension/Core/EventListener/MergeCollectionListener.php b/src/Symfony/Component/Form/Extension/Core/EventListener/MergeCollectionListener.php
index f69775825d..52a73a8f0b 100644
--- a/src/Symfony/Component/Form/Extension/Core/EventListener/MergeCollectionListener.php
+++ b/src/Symfony/Component/Form/Extension/Core/EventListener/MergeCollectionListener.php
@@ -70,6 +70,13 @@ class MergeCollectionListener implements EventSubscriberInterface
     public function onBindNormData(FilterDataEvent $event)
     {
         $originalData = $event->getForm()->getData();
+
+        // If we are not allowed to change anything, return immediately
+        if (!$this->allowAdd && !$this->allowDelete) {
+            $event->setData($originalData);
+            return;
+        }
+
         $form = $event->getForm();
         $data = $event->getData();
         $parentData = $form->hasParent() ? $form->getParent()->getData() : null;
@@ -98,21 +105,33 @@ class MergeCollectionListener implements EventSubscriberInterface
                 $adderName = $this->adderPrefix . $singular;
                 $removerName = $this->removerPrefix . $singular;
 
-                if ($reflClass->hasMethod($adderName) && $reflClass->hasMethod($removerName)) {
+                if ($this->allowAdd && $reflClass->hasMethod($adderName)) {
                     $adder = $reflClass->getMethod($adderName);
+
+                    if (!$adder->isPublic() || $adder->getNumberOfRequiredParameters() !== 1) {
+                        // False alert
+                        $adder = null;
+                    }
+                }
+
+                if ($this->allowDelete && $reflClass->hasMethod($removerName)) {
                     $remover = $reflClass->getMethod($removerName);
 
-                    if ($adder->isPublic() && $adder->getNumberOfRequiredParameters() === 1
-                        && $remover->isPublic() && $remover->getNumberOfRequiredParameters() === 1) {
-
-                        // We found a public, one-parameter add and remove method
-                        break;
+                    if (!$remover->isPublic() || $remover->getNumberOfRequiredParameters() !== 1) {
+                        // False alert
+                        $remover = null;
                     }
-
-                    // False alert
-                    $adder = null;
-                    $remover = null;
                 }
+
+                // When we want to both add and delete, we look for an adder and
+                // remover with the same name
+                if (!($this->allowAdd && !$adder) && !($this->allowDelete && !$remover)) {
+                    break;
+                }
+
+                // False alert
+                $adder = null;
+                $remover = null;
             }
         }
 
@@ -136,15 +155,15 @@ class MergeCollectionListener implements EventSubscriberInterface
             }
         }
 
-        if ($adder && $remover) {
+        if ($adder || $remover) {
             // If methods to add and to remove exist, call them now, if allowed
-            if ($this->allowDelete) {
+            if ($remover) {
                 foreach ($itemsToDelete as $item) {
                     $remover->invoke($parentData, $item);
                 }
             }
 
-            if ($this->allowAdd) {
+            if ($adder) {
                 foreach ($itemsToAdd as $item) {
                     $adder->invoke($parentData, $item);
                 }
diff --git a/tests/Symfony/Tests/Component/Form/Extension/Core/EventListener/MergeCollectionListenerTest.php b/tests/Symfony/Tests/Component/Form/Extension/Core/EventListener/MergeCollectionListenerTest.php
index a8f56c46fe..84f17ada78 100644
--- a/tests/Symfony/Tests/Component/Form/Extension/Core/EventListener/MergeCollectionListenerTest.php
+++ b/tests/Symfony/Tests/Component/Form/Extension/Core/EventListener/MergeCollectionListenerTest.php
@@ -31,6 +31,16 @@ class MergeCollectionListenerTest_CarCustomPrefix
     public function barAxis($axis) {}
 }
 
+class MergeCollectionListenerTest_CarOnlyAdder
+{
+    public function addAxis($axis) {}
+}
+
+class MergeCollectionListenerTest_CarOnlyRemover
+{
+    public function removeAxis($axis) {}
+}
+
 abstract class MergeCollectionListenerTest extends \PHPUnit_Framework_TestCase
 {
     private $dispatcher;
@@ -177,7 +187,7 @@ abstract class MergeCollectionListenerTest extends \PHPUnit_Framework_TestCase
     {
         $newData = 'no array or traversable';
         $event = new FilterDataEvent($this->form, $newData);
-        $listener = new MergeCollectionListener(false, false);
+        $listener = new MergeCollectionListener(true, false);
         $listener->onBindNormData($event);
     }
 
@@ -225,7 +235,7 @@ abstract class MergeCollectionListenerTest extends \PHPUnit_Framework_TestCase
 
     public function testCallAdderIfAllowAdd()
     {
-        $parentData = $this->getMock(__CLASS__ . '_Car');
+        $parentData = $this->getMock(__CLASS__ . '_CarOnlyAdder');
         $parentForm = $this->getForm('car');
         $parentForm->setData($parentData);
         $parentForm->add($this->form);
@@ -313,7 +323,7 @@ abstract class MergeCollectionListenerTest extends \PHPUnit_Framework_TestCase
 
     public function testCallRemoverIfAllowDelete()
     {
-        $parentData = $this->getMock(__CLASS__ . '_Car');
+        $parentData = $this->getMock(__CLASS__ . '_CarOnlyRemover');
         $parentForm = $this->getForm('car');
         $parentForm->setData($parentData);
         $parentForm->add($this->form);
@@ -399,6 +409,39 @@ abstract class MergeCollectionListenerTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals($newData, $event->getData());
     }
 
+    public function testCallAdderAndDeleterIfAllowAll()
+    {
+        $parentData = $this->getMock(__CLASS__ . '_Car');
+        $parentForm = $this->getForm('car');
+        $parentForm->setData($parentData);
+        $parentForm->add($this->form);
+
+        $originalDataArray = array(1 => 'second');
+        $originalData = $this->getData($originalDataArray);
+        $newData = $this->getData(array(0 => 'first'));
+
+        $this->form->setData($originalData);
+
+        $parentData->expects($this->once())
+            ->method('addAxis')
+            ->with('first');
+        $parentData->expects($this->once())
+            ->method('removeAxis')
+            ->with('second');
+
+        $event = new FilterDataEvent($this->form, $newData);
+        $listener = new MergeCollectionListener(true, true, true);
+        $listener->onBindNormData($event);
+
+        if (is_object($originalData)) {
+            $this->assertSame($originalData, $event->getData());
+        }
+
+        // The data was not modified directly
+        // Thus it should not be written back into the parent data!
+        $this->assertEquals($this->getData($originalDataArray), $event->getData());
+    }
+
     public function testCallAccessorsWithCustomPrefixes()
     {
         $parentData = $this->getMock(__CLASS__ . '_CarCustomPrefix');