diff --git a/src/Symfony/Component/HttpKernel/Debug/Stopwatch.php b/src/Symfony/Component/HttpKernel/Debug/Stopwatch.php
index cf2d10ee43..06aa36a8d8 100644
--- a/src/Symfony/Component/HttpKernel/Debug/Stopwatch.php
+++ b/src/Symfony/Component/HttpKernel/Debug/Stopwatch.php
@@ -42,13 +42,17 @@ class Stopwatch
     /**
      * Stops the last started section.
      *
+     * The id parameter is used to retrieve the events from this section.
+     *
+     * @see getSectionEvents
+     *
      * @param string $id The identifier of the section
      */
     public function stopSection($id)
     {
         $this->stop('section');
 
-        if ($id) {
+        if (null !== $id) {
             $this->sections[$id] = $this->events;
         }
 
@@ -74,9 +78,8 @@ class Stopwatch
         if (!isset($this->events[$name])) {
             $this->events[$name] = new StopwatchEvent($this->origin, $category);
         }
-        $this->events[$name]->start();
 
-        return $this->events[$name];
+        return $this->events[$name]->start();
     }
 
     /**
@@ -92,9 +95,7 @@ class Stopwatch
             throw new \LogicException(sprintf('Event "%s" is not started.', $name));
         }
 
-        $this->events[$name]->stop();
-
-        return $this->events[$name];
+        return $this->events[$name]->stop();
     }
 
     /**
@@ -106,9 +107,7 @@ class Stopwatch
      */
     public function lap($name)
     {
-        $this->stop($name);
-
-        return $this->start($name);
+        return $this->stop($name)->start();
     }
 
     /**
diff --git a/src/Symfony/Component/HttpKernel/Debug/StopwatchEvent.php b/src/Symfony/Component/HttpKernel/Debug/StopwatchEvent.php
index 4965418596..9796175ae5 100644
--- a/src/Symfony/Component/HttpKernel/Debug/StopwatchEvent.php
+++ b/src/Symfony/Component/HttpKernel/Debug/StopwatchEvent.php
@@ -32,7 +32,7 @@ class StopwatchEvent
     public function __construct($origin, $category = null)
     {
         $this->origin = $origin;
-        $this->category = $category ?: 'default';
+        $this->category = is_string($category) ? $category : 'default';
         $this->started = array();
         $this->periods = array();
     }
@@ -59,14 +59,20 @@ class StopwatchEvent
 
     /**
      * Starts a new event period.
+     *
+     * @return StopwatchEvent The event.
      */
     public function start()
     {
         $this->started[] = $this->getNow();
+
+        return $this;
     }
 
     /**
      * Stops the last started event period.
+     *
+     * @return StopwatchEvent The event.
      */
     public function stop()
     {
@@ -75,15 +81,18 @@ class StopwatchEvent
         }
 
         $this->periods[] = array(array_pop($this->started), $this->getNow());
+
+        return $this;
     }
 
     /**
      * Stops the current period and then starts a new one.
+     *
+     * @return StopwatchEvent The event.
      */
     public function lap()
     {
-        $this->stop();
-        $this->start();
+        return $this->stop()->start();
     }
 
     /**
diff --git a/tests/Symfony/Tests/Component/HttpKernel/Debug/StopwatchTest.php b/tests/Symfony/Tests/Component/HttpKernel/Debug/StopwatchTest.php
index ea7ee2d19e..486af75714 100644
--- a/tests/Symfony/Tests/Component/HttpKernel/Debug/StopwatchTest.php
+++ b/tests/Symfony/Tests/Component/HttpKernel/Debug/StopwatchTest.php
@@ -73,15 +73,22 @@ class StopwatchTest extends \PHPUnit_Framework_TestCase
         $stopwatch->stop('foo');
         $stopwatch->start('bar', 'cat');
         $stopwatch->stop('bar');
-        $stopwatch->stopSection(1);
+        $stopwatch->stopSection('1');
 
         $stopwatch->startSection();
         $stopwatch->start('foobar', 'cat');
         $stopwatch->stop('foobar');
-        $stopwatch->stopSection(2);
+        $stopwatch->stopSection('2');
+
+        $stopwatch->startSection();
+        $stopwatch->start('foobar', 'cat');
+        $stopwatch->stop('foobar');
+        $stopwatch->stopSection('0');
+
 
         // the section is an event by itself
-        $this->assertEquals(3, count($stopwatch->getSectionEvents(1)));
-        $this->assertEquals(2, count($stopwatch->getSectionEvents(2)));
+        $this->assertEquals(3, count($stopwatch->getSectionEvents('1')));
+        $this->assertEquals(2, count($stopwatch->getSectionEvents('2')));
+        $this->assertEquals(2, count($stopwatch->getSectionEvents('0')));
     }
 }