diff --git a/src/Invoice/Calculator/AbstractMergedCalculator.php b/src/Invoice/Calculator/AbstractMergedCalculator.php
index d66c0478..44513833 100644
--- a/src/Invoice/Calculator/AbstractMergedCalculator.php
+++ b/src/Invoice/Calculator/AbstractMergedCalculator.php
@@ -47,11 +47,12 @@ abstract class AbstractMergedCalculator extends AbstractCalculator
             $invoiceItem->setEnd($entry->getEnd());
         }
 
-        if (null !== $this->model->getQuery()->getActivity()) {
-            $invoiceItem->setActivity($this->model->getQuery()->getActivity());
-            $invoiceItem->setDescription($this->model->getQuery()->getActivity()->getName());
-        } elseif (null !== $this->model->getQuery()->getProject()) {
-            $invoiceItem->setDescription($this->model->getQuery()->getProject()->getName());
+        if (!empty($entry->getDescription())) {
+            $description = '';
+            if (!empty($invoiceItem->getDescription())) {
+                $description = $invoiceItem->getDescription() . PHP_EOL;
+            }
+            $invoiceItem->setDescription($description . $entry->getDescription());
         }
 
         if (null === $invoiceItem->getActivity()) {
diff --git a/src/Invoice/Calculator/AbstractSumInvoiceCalculator.php b/src/Invoice/Calculator/AbstractSumInvoiceCalculator.php
index f1d3153c..de16c037 100644
--- a/src/Invoice/Calculator/AbstractSumInvoiceCalculator.php
+++ b/src/Invoice/Calculator/AbstractSumInvoiceCalculator.php
@@ -47,8 +47,14 @@ abstract class AbstractSumInvoiceCalculator extends AbstractMergedCalculator imp
             }
             $timesheet = $invoiceItems[$id];
             $this->mergeTimesheets($timesheet, $entry);
+            $this->mergeSumTimesheet($timesheet, $entry);
         }
 
         return array_values($invoiceItems);
     }
+
+    protected function mergeSumTimesheet(InvoiceItem $invoiceItem, Timesheet $entry)
+    {
+        // allows to set values per calculator after merging the timesheet
+    }
 }
diff --git a/src/Invoice/Calculator/ActivityInvoiceCalculator.php b/src/Invoice/Calculator/ActivityInvoiceCalculator.php
index e6a9beea..4702f025 100644
--- a/src/Invoice/Calculator/ActivityInvoiceCalculator.php
+++ b/src/Invoice/Calculator/ActivityInvoiceCalculator.php
@@ -11,6 +11,7 @@ namespace App\Invoice\Calculator;
 
 use App\Entity\Timesheet;
 use App\Invoice\CalculatorInterface;
+use App\Invoice\InvoiceItem;
 
 /**
  * A calculator that sums up the timesheet records by activity.
@@ -26,6 +27,12 @@ class ActivityInvoiceCalculator extends AbstractSumInvoiceCalculator implements
         return (string) $timesheet->getActivity()->getId();
     }
 
+    protected function mergeSumTimesheet(InvoiceItem $invoiceItem, Timesheet $entry)
+    {
+        $invoiceItem->setActivity($entry->getActivity());
+        $invoiceItem->setDescription($entry->getActivity()->getName());
+    }
+
     /**
      * @return string
      */
diff --git a/src/Invoice/Calculator/ProjectInvoiceCalculator.php b/src/Invoice/Calculator/ProjectInvoiceCalculator.php
index 87fd875a..05106229 100644
--- a/src/Invoice/Calculator/ProjectInvoiceCalculator.php
+++ b/src/Invoice/Calculator/ProjectInvoiceCalculator.php
@@ -11,6 +11,7 @@ namespace App\Invoice\Calculator;
 
 use App\Entity\Timesheet;
 use App\Invoice\CalculatorInterface;
+use App\Invoice\InvoiceItem;
 
 /**
  * A calculator that sums up the timesheet records by project.
@@ -26,6 +27,12 @@ class ProjectInvoiceCalculator extends AbstractSumInvoiceCalculator implements C
         return (string) $timesheet->getProject()->getId();
     }
 
+    protected function mergeSumTimesheet(InvoiceItem $invoiceItem, Timesheet $entry)
+    {
+        $invoiceItem->setProject($entry->getProject());
+        $invoiceItem->setDescription($entry->getProject()->getName());
+    }
+
     /**
      * @return string
      */
diff --git a/src/Invoice/Calculator/UserInvoiceCalculator.php b/src/Invoice/Calculator/UserInvoiceCalculator.php
index e67256de..26c8d173 100644
--- a/src/Invoice/Calculator/UserInvoiceCalculator.php
+++ b/src/Invoice/Calculator/UserInvoiceCalculator.php
@@ -9,37 +9,21 @@
 
 namespace App\Invoice\Calculator;
 
+use App\Entity\Timesheet;
 use App\Invoice\CalculatorInterface;
-use App\Invoice\InvoiceItem;
 
 /**
  * A calculator that sums up the timesheet records by user.
  */
-class UserInvoiceCalculator extends AbstractMergedCalculator implements CalculatorInterface
+class UserInvoiceCalculator extends AbstractSumInvoiceCalculator implements CalculatorInterface
 {
-    /**
-     * @return InvoiceItem[]
-     */
-    public function getEntries()
+    protected function calculateSumIdentifier(Timesheet $timesheet): string
     {
-        $entries = $this->model->getEntries();
-        if (empty($entries)) {
-            return [];
+        if (null === $timesheet->getUser()->getId()) {
+            throw new \Exception('Cannot handle un-persisted user');
         }
 
-        /** @var InvoiceItem[] $invoiceItems */
-        $invoiceItems = [];
-
-        foreach ($entries as $entry) {
-            $id = $entry->getUser()->getId();
-            if (!isset($invoiceItems[$id])) {
-                $invoiceItems[$id] = new InvoiceItem();
-            }
-            $invoiceItem = $invoiceItems[$id];
-            $this->mergeTimesheets($invoiceItem, $entry);
-        }
-
-        return array_values($invoiceItems);
+        return (string) $timesheet->getUser()->getId();
     }
 
     /**
diff --git a/templates/invoice/renderer/default.html.twig b/templates/invoice/renderer/default.html.twig
index 12983995..9c625567 100644
--- a/templates/invoice/renderer/default.html.twig
+++ b/templates/invoice/renderer/default.html.twig
@@ -75,9 +75,9 @@
                 {% endif %}
                 <tr>
                     <td>{{ entry.begin|date_short }}</td>
-                    <td>
+                    <td contenteditable="true">
                         {% if entry.description is not empty %}
-                            {{ entry.description }}
+                            {{ entry.description|nl2br }}
                         {% else %}
                             {{ entry.activity.name }} / {{ entry.project.name }}
                         {% endif %}
diff --git a/templates/invoice/renderer/freelancer.html.twig b/templates/invoice/renderer/freelancer.html.twig
index e74c5d70..30d866c2 100644
--- a/templates/invoice/renderer/freelancer.html.twig
+++ b/templates/invoice/renderer/freelancer.html.twig
@@ -90,7 +90,7 @@
                     <tr>
                         <td contenteditable="true">
                             {% if entry.description is not empty %}
-                                {{ entry.description }}
+                                {{ entry.description|nl2br }}
                             {% else %}
                                 {{ entry.activity.name }} / {{ entry.project.name }}
                             {% endif %}
diff --git a/templates/invoice/renderer/timesheet.html.twig b/templates/invoice/renderer/timesheet.html.twig
index f2364dc9..f8842d22 100644
--- a/templates/invoice/renderer/timesheet.html.twig
+++ b/templates/invoice/renderer/timesheet.html.twig
@@ -72,9 +72,9 @@
                 {% if model.query.user is empty %}
                     <td>{{ widgets.username(entry.user) }}</td>
                 {% endif %}
-                <td>
+                <td contenteditable="true">
                     {% if entry.description is not empty %}
-                        {{ entry.description }}
+                        {{ entry.description|nl2br }}
                     {% else %}
                         {{ entry.activity.name }} / {{ entry.project.name }}
                     {% endif %}
diff --git a/tests/Invoice/Calculator/AbstractCalculatorTest.php b/tests/Invoice/Calculator/AbstractCalculatorTest.php
index 8d44da0f..c2949e73 100644
--- a/tests/Invoice/Calculator/AbstractCalculatorTest.php
+++ b/tests/Invoice/Calculator/AbstractCalculatorTest.php
@@ -50,24 +50,19 @@ abstract class AbstractCalculatorTest extends TestCase
         $template = new InvoiceTemplate();
         $template->setVat(19);
 
+        $user = $this->getMockBuilder(User::class)->setMethods(['getId'])->disableOriginalConstructor()->getMock();
+        $user->method('getId')->willReturn(1);
+
         $project = $this->getMockBuilder(Project::class)->setMethods(['getId', 'getCustomer', 'getName'])->disableOriginalConstructor()->getMock();
         $project->method('getId')->willReturn(1);
         $project->method('getCustomer')->willReturn($customer);
         $project->method('getName')->willReturn('project description');
 
-        $project1 = $this->getMockBuilder(Project::class)->setMethods(['getId', 'getName'])->disableOriginalConstructor()->getMock();
-        $project1->method('getId')->willReturn(1);
-        $project1->method('getName')->willReturn('bar');
-
         $activity = $this->getMockBuilder(Activity::class)->setMethods(['getId', 'getProject', 'getName'])->disableOriginalConstructor()->getMock();
         $activity->method('getId')->willReturn(1);
         $activity->method('getProject')->willReturn($project);
         $activity->method('getName')->willReturn('activity description');
 
-        $activity1 = $this->getMockBuilder(Activity::class)->setMethods(['getId', 'getName'])->disableOriginalConstructor()->getMock();
-        $activity1->method('getId')->willReturn(1);
-        $activity1->method('getName')->willReturn('foo');
-
         $query = new InvoiceQuery();
         if ($addProject === true) {
             $query->setProject($project);
@@ -81,9 +76,9 @@ abstract class AbstractCalculatorTest extends TestCase
             ->setBegin(new \DateTime())
             ->setDuration(3600)
             ->setRate(293.27)
-            ->setUser(new User())
-            ->setActivity($activity1)
-            ->setProject($project1);
+            ->setUser($user)
+            ->setActivity($activity)
+            ->setProject($project);
 
         $model = new InvoiceModel();
         $model->setCustomer($customer);
@@ -101,7 +96,7 @@ abstract class AbstractCalculatorTest extends TestCase
         } elseif ($addActivity === true) {
             $this->assertEquals('activity description', $result->getDescription());
         } else {
-            $this->assertEquals('foo', $result->getDescription());
+            $this->assertEquals('timesheet description', $result->getDescription());
         }
     }
 }
diff --git a/tests/Invoice/Calculator/ActivityInvoiceCalculatorTest.php b/tests/Invoice/Calculator/ActivityInvoiceCalculatorTest.php
index 13d7da59..2198e5b8 100644
--- a/tests/Invoice/Calculator/ActivityInvoiceCalculatorTest.php
+++ b/tests/Invoice/Calculator/ActivityInvoiceCalculatorTest.php
@@ -128,18 +128,8 @@ class ActivityInvoiceCalculatorTest extends AbstractCalculatorTest
         $this->assertEquals(84, $entries[2]->getRate());
     }
 
-    public function testDescriptionByTimesheet()
-    {
-        $this->assertDescription(new ActivityInvoiceCalculator(), false, false);
-    }
-
     public function testDescriptionByActivity()
     {
         $this->assertDescription(new ActivityInvoiceCalculator(), false, true);
     }
-
-    public function testDescriptionByProject()
-    {
-        $this->assertDescription(new ActivityInvoiceCalculator(), true, false);
-    }
 }
diff --git a/tests/Invoice/Calculator/DateInvoiceCalculatorTest.php b/tests/Invoice/Calculator/DateInvoiceCalculatorTest.php
index 2116acdf..a2a3f0fb 100644
--- a/tests/Invoice/Calculator/DateInvoiceCalculatorTest.php
+++ b/tests/Invoice/Calculator/DateInvoiceCalculatorTest.php
@@ -135,14 +135,4 @@ class DateInvoiceCalculatorTest extends AbstractCalculatorTest
     {
         $this->assertDescription(new DateInvoiceCalculator(), false, false);
     }
-
-    public function testDescriptionByActivity()
-    {
-        $this->assertDescription(new DateInvoiceCalculator(), false, true);
-    }
-
-    public function testDescriptionByProject()
-    {
-        $this->assertDescription(new DateInvoiceCalculator(), true, false);
-    }
 }
diff --git a/tests/Invoice/Calculator/DefaultCalculatorTest.php b/tests/Invoice/Calculator/DefaultCalculatorTest.php
index 7f20c3ca..fda1ffe3 100644
--- a/tests/Invoice/Calculator/DefaultCalculatorTest.php
+++ b/tests/Invoice/Calculator/DefaultCalculatorTest.php
@@ -35,18 +35,21 @@ class DefaultCalculatorTest extends AbstractCalculatorTest
         $template->setVat(19);
 
         $timesheet = new Timesheet();
+        $timesheet->setDescription('foo 1');
         $timesheet->setBegin(new \DateTime());
         $timesheet->setDuration(3600);
         $timesheet->setRate(293.27);
         $timesheet->setActivity(new Activity());
 
         $timesheet2 = new Timesheet();
+        $timesheet2->setDescription('foo 2');
         $timesheet2->setBegin(new \DateTime());
         $timesheet2->setDuration(400);
         $timesheet2->setRate(84);
         $timesheet2->setActivity(new Activity());
 
         $timesheet3 = new Timesheet();
+        $timesheet3->setDescription('foo 3');
         $timesheet3->setBegin(new \DateTime());
         $timesheet3->setDuration(1800);
         $timesheet3->setRate(111.11);
diff --git a/tests/Invoice/Calculator/ProjectInvoiceCalculatorTest.php b/tests/Invoice/Calculator/ProjectInvoiceCalculatorTest.php
index efc40e48..385a7206 100644
--- a/tests/Invoice/Calculator/ProjectInvoiceCalculatorTest.php
+++ b/tests/Invoice/Calculator/ProjectInvoiceCalculatorTest.php
@@ -131,16 +131,6 @@ class ProjectInvoiceCalculatorTest extends AbstractCalculatorTest
         self::assertEquals(2521.12, $entries[0]->getRate() + $entries[1]->getRate() + $entries[2]->getRate());
     }
 
-    public function testDescriptionByTimesheet()
-    {
-        $this->assertDescription(new ProjectInvoiceCalculator(), false, false);
-    }
-
-    public function testDescriptionByActivity()
-    {
-        $this->assertDescription(new ProjectInvoiceCalculator(), false, true);
-    }
-
     public function testDescriptionByProject()
     {
         $this->assertDescription(new ProjectInvoiceCalculator(), true, false);
diff --git a/tests/Invoice/Calculator/ShortInvoiceCalculatorTest.php b/tests/Invoice/Calculator/ShortInvoiceCalculatorTest.php
index 1f784282..8bb8b88d 100644
--- a/tests/Invoice/Calculator/ShortInvoiceCalculatorTest.php
+++ b/tests/Invoice/Calculator/ShortInvoiceCalculatorTest.php
@@ -190,14 +190,4 @@ class ShortInvoiceCalculatorTest extends AbstractCalculatorTest
     {
         $this->assertDescription(new ShortInvoiceCalculator(), false, false);
     }
-
-    public function testDescriptionByActivity()
-    {
-        $this->assertDescription(new ShortInvoiceCalculator(), false, true);
-    }
-
-    public function testDescriptionByProject()
-    {
-        $this->assertDescription(new ShortInvoiceCalculator(), true, false);
-    }
 }
diff --git a/tests/Invoice/Calculator/UserInvoiceCalculatorTest.php b/tests/Invoice/Calculator/UserInvoiceCalculatorTest.php
index 1b699140..60fd8509 100644
--- a/tests/Invoice/Calculator/UserInvoiceCalculatorTest.php
+++ b/tests/Invoice/Calculator/UserInvoiceCalculatorTest.php
@@ -46,6 +46,9 @@ class UserInvoiceCalculatorTest extends AbstractCalculatorTest
         $user2 = $this->getMockBuilder(User::class)->setMethods(['getId'])->disableOriginalConstructor()->getMock();
         $user2->method('getId')->willReturn(2);
 
+        $user3 = $this->getMockBuilder(User::class)->setMethods(['getId'])->disableOriginalConstructor()->getMock();
+        $user3->method('getId')->willReturn(3);
+
         $timesheet = new Timesheet();
         $timesheet
             ->setBegin(new \DateTime())
@@ -92,7 +95,7 @@ class UserInvoiceCalculatorTest extends AbstractCalculatorTest
             ->setEnd(new \DateTime())
             ->setDuration(400)
             ->setRate(84)
-            ->setUser(new User())
+            ->setUser($user3)
             ->setActivity($activity)
             ->setProject((new Project())->setName('bar'));
 
@@ -128,14 +131,4 @@ class UserInvoiceCalculatorTest extends AbstractCalculatorTest
     {
         $this->assertDescription(new UserInvoiceCalculator(), false, false);
     }
-
-    public function testDescriptionByActivity()
-    {
-        $this->assertDescription(new UserInvoiceCalculator(), false, true);
-    }
-
-    public function testDescriptionByProject()
-    {
-        $this->assertDescription(new UserInvoiceCalculator(), true, false);
-    }
 }