diff --git a/src/Bundle/ChillCalendarBundle/Controller/CalendarController.php b/src/Bundle/ChillCalendarBundle/Controller/CalendarController.php
index 2eb04fca9..ec53cff1b 100644
--- a/src/Bundle/ChillCalendarBundle/Controller/CalendarController.php
+++ b/src/Bundle/ChillCalendarBundle/Controller/CalendarController.php
@@ -284,12 +284,8 @@ class CalendarController extends AbstractController
         $entity = new Calendar();
         if ($request->query->has('mainUser')) {
             $entity->setMainUser($this->userRepository->find($request->query->getInt('mainUser')));
-        } else {
-            $entity->setMainUser($this->getUser());
         }
 
-        dump($entity);
-
         // if ($user instanceof User) {
         //     $entity->setPerson($user);
         // }
diff --git a/src/Bundle/ChillCalendarBundle/Entity/Calendar.php b/src/Bundle/ChillCalendarBundle/Entity/Calendar.php
index e6c5a8e97..63803efda 100644
--- a/src/Bundle/ChillCalendarBundle/Entity/Calendar.php
+++ b/src/Bundle/ChillCalendarBundle/Entity/Calendar.php
@@ -172,6 +172,29 @@ class Calendar implements TrackCreationInterface, TrackUpdateInterface
         return $this;
     }
 
+    public function addUser(User $user): self
+    {
+        if (!$this->getUsers()->contains($user)) {
+            $this->addInvite((new Invite())->setUser($user));
+        }
+
+        return $this;
+    }
+
+    public function removeUser(User $user): self
+    {
+        if (!$this->getUsers()->contains($user)) {
+            return $this;
+        }
+
+        $invite = $this->invites
+            ->filter(function (Invite $invite) use ($user) { return $invite->getUser() === $user; })
+            ->first();
+        $this->removeInvite($invite);
+
+        return $this;
+    }
+
     public function addPerson(Person $person): self
     {
         $this->persons[] = $person;
@@ -309,14 +332,12 @@ class Calendar implements TrackCreationInterface, TrackUpdateInterface
         return $this->getProfessionals();
     }
 
-    public function getUser(): ?User
+    /**
+     * @return Collection|User[]
+     */
+    public function getUsers(): Collection
     {
-        return $this->user;
-    }
-
-    public function getusers(): Collection
-    {
-        return $this->getInvites(); //TODO get users of the invite
+        return $this->getInvites()->map(function (Invite $i) { return $i->getUser(); });
     }
 
     public static function loadValidatorMetadata(ClassMetadata $metadata): void
@@ -335,7 +356,9 @@ class Calendar implements TrackCreationInterface, TrackUpdateInterface
 
     public function removeInvite(Invite $invite): self
     {
-        $this->invites->removeElement($invite);
+        if ($this->invites->removeElement($invite)) {
+            $invite->setCalendar(null);
+        }
 
         return $this;
     }
diff --git a/src/Bundle/ChillCalendarBundle/Entity/Invite.php b/src/Bundle/ChillCalendarBundle/Entity/Invite.php
index fac0a833b..96713ed2a 100644
--- a/src/Bundle/ChillCalendarBundle/Entity/Invite.php
+++ b/src/Bundle/ChillCalendarBundle/Entity/Invite.php
@@ -40,14 +40,14 @@ class Invite implements TrackUpdateInterface, TrackCreationInterface
     /**
      * @ORM\ManyToOne(targetEntity=Calendar::class, inversedBy="invites")
      */
-    private ?Calendar $calendar;
+    private ?Calendar $calendar = null;
 
     /**
      * @ORM\Id
      * @ORM\GeneratedValue
      * @ORM\Column(type="integer")
      */
-    private ?int $id;
+    private ?int $id = null;
 
     /**
      * @ORM\Column(type="text", nullable=false, options={"default": "pending"})
@@ -58,7 +58,7 @@ class Invite implements TrackUpdateInterface, TrackCreationInterface
      * @ORM\ManyToOne(targetEntity="Chill\MainBundle\Entity\User")
      * @ORM\JoinColumn(nullable=false)
      */
-    private ?User $user;
+    private ?User $user = null;
 
     public function getCalendar(): ?Calendar
     {
@@ -82,8 +82,6 @@ class Invite implements TrackUpdateInterface, TrackCreationInterface
 
     /**
      * @internal use Calendar::addInvite instead
-     * @param Calendar|null $calendar
-     * @return void
      */
     public function setCalendar(?Calendar $calendar): void
     {
@@ -99,6 +97,10 @@ class Invite implements TrackUpdateInterface, TrackCreationInterface
 
     public function setUser(?User $user): self
     {
+        if ($user instanceof User && $this->user instanceof User && $user !== $this->user) {
+            throw new \LogicException("Not allowed to associate an invite to a different user");
+        }
+
         $this->user = $user;
 
         return $this;
diff --git a/src/Bundle/ChillCalendarBundle/Form/CalendarType.php b/src/Bundle/ChillCalendarBundle/Form/CalendarType.php
index 74ad6343a..35f0b5075 100644
--- a/src/Bundle/ChillCalendarBundle/Form/CalendarType.php
+++ b/src/Bundle/ChillCalendarBundle/Form/CalendarType.php
@@ -70,6 +70,7 @@ class CalendarType extends AbstractType
 
         if ($options['data'] instanceof Calendar && $options['data']->getId() === null) {
             $builder->add('mainUser', PickUserDynamicType::class, [
+                'multiple' => false,
                 'required' => true,
                 'help' => 'chill_calendar.form.The main user is mandatory. He will organize the appointment.',
             ]);
@@ -192,26 +193,6 @@ class CalendarType extends AbstractType
                     return $this->om->getRepository(Location::class)->findOneBy(['id' => (int) $id]);
                 }
             ));
-
-        $builder->add('invites', HiddenType::class);
-        $builder->get('invites')
-            ->addModelTransformer(new CallbackTransformer(
-                static function (iterable $usersAsIterable): string {
-                    $userIds = [];
-
-                    foreach ($usersAsIterable as $value) {
-                        $userIds[] = $value->getId();
-                    }
-
-                    return implode(',', $userIds);
-                },
-                function (?string $usersAsString): array {
-                    return array_map(
-                        fn (string $id): ?Invite => $this->om->getRepository(Invite::class)->findOneBy(['id' => (int) $id]),
-                        explode(',', $usersAsString)
-                    );
-                }
-            ));
     }
 
     public function configureOptions(OptionsResolver $resolver)
diff --git a/src/Bundle/ChillCalendarBundle/Resources/public/vuejs/Calendar/store.js b/src/Bundle/ChillCalendarBundle/Resources/public/vuejs/Calendar/store.js
index a0d5a8715..408d68147 100644
--- a/src/Bundle/ChillCalendarBundle/Resources/public/vuejs/Calendar/store.js
+++ b/src/Bundle/ChillCalendarBundle/Resources/public/vuejs/Calendar/store.js
@@ -180,8 +180,8 @@ const store = createStore({
          startDateInput.value = payload.startStr;
          let endDateInput = document.getElementById("chill_activitybundle_activity_endDate");
          endDateInput.value = payload.endStr;
-         let mainUserInput = document.getElementById("chill_activitybundle_activity_mainUser");
-         mainUserInput.value = payload.users.logged.id;
+         //let mainUserInput = document.getElementById("chill_activitybundle_activity_mainUser");
+         //mainUserInput.value = payload.users.logged.id;
          commit('setEvents', payload);
       },
       updateEvent({ commit }, payload) {
@@ -192,8 +192,8 @@ const store = createStore({
          endDateInput.value = payload.event.end.toISOString();
          let calendarRangeInput = document.getElementById("chill_activitybundle_activity_calendarRange");
          calendarRangeInput.value = Number(payload.event.extendedProps.calendarRangeId);
-         let mainUserInput = document.getElementById("chill_activitybundle_activity_mainUser");
-         mainUserInput.value = Number(payload.event.source.id);
+         //let mainUserInput = document.getElementById("chill_activitybundle_activity_mainUser");
+         //mainUserInput.value = Number(payload.event.source.id);
          commit('setEvents', payload);
       },
 
diff --git a/src/Bundle/ChillCalendarBundle/Tests/Entity/CalendarTest.php b/src/Bundle/ChillCalendarBundle/Tests/Entity/CalendarTest.php
new file mode 100644
index 000000000..c6d7b73a7
--- /dev/null
+++ b/src/Bundle/ChillCalendarBundle/Tests/Entity/CalendarTest.php
@@ -0,0 +1,44 @@
+<?php
+
+namespace Chill\CalendarBundle\Tests\Entity;
+
+use Chill\CalendarBundle\Entity\Calendar;
+use Chill\MainBundle\Entity\User;
+use PHPUnit\Framework\TestCase;
+
+class CalendarTest extends TestCase
+{
+    public function testAddUser()
+    {
+        $calendar = new Calendar();
+
+        $this->assertCount(0, $calendar->getInvites());
+        $this->assertCount(0, $calendar->getUsers());
+
+        $calendar->addUser($user0 = new User());
+
+        $this->assertCount(1, $calendar->getInvites());
+        $this->assertCount(1, $calendar->getUsers());
+        $this->assertSame($user0, $calendar->getUsers()->first());
+
+        $calendar->addUser($user1 = new User());
+
+        $this->assertCount(2, $calendar->getInvites());
+        $this->assertCount(2, $calendar->getUsers());
+        $this->assertContains($user0, $calendar->getUsers());
+        $this->assertContains($user1, $calendar->getUsers());
+
+        $calendar->removeUser($user0);
+
+        $this->assertCount(1, $calendar->getInvites());
+        $this->assertCount(1, $calendar->getUsers());
+        $this->assertNotSame($user0, $calendar->getUsers()->first());
+        $this->assertSame($user1, $calendar->getUsers()->first());
+
+        $calendar->removeUser($user1);
+
+        $this->assertCount(0, $calendar->getInvites());
+        $this->assertCount(0, $calendar->getUsers());
+    }
+
+}
diff --git a/src/Bundle/ChillMainBundle/Form/Type/DataTransformer/EntityToJsonTransformer.php b/src/Bundle/ChillMainBundle/Form/Type/DataTransformer/EntityToJsonTransformer.php
index 95c447119..1795741a1 100644
--- a/src/Bundle/ChillMainBundle/Form/Type/DataTransformer/EntityToJsonTransformer.php
+++ b/src/Bundle/ChillMainBundle/Form/Type/DataTransformer/EntityToJsonTransformer.php
@@ -43,6 +43,9 @@ class EntityToJsonTransformer implements DataTransformerInterface
 
     public function reverseTransform($value)
     {
+        dump($value);
+        dump($this->type);
+        dump($this->multiple);
         $denormalized = json_decode($value, true);
 
         if ($this->multiple) {
diff --git a/src/Bundle/ChillMainBundle/Repository/LocationRepository.php b/src/Bundle/ChillMainBundle/Repository/LocationRepository.php
index 253298d49..26c338d39 100644
--- a/src/Bundle/ChillMainBundle/Repository/LocationRepository.php
+++ b/src/Bundle/ChillMainBundle/Repository/LocationRepository.php
@@ -13,6 +13,7 @@ namespace Chill\MainBundle\Repository;
 
 use Chill\MainBundle\Entity\Location;
 use Doctrine\Bundle\DoctrineBundle\Repository\ServiceEntityRepository;
+use Doctrine\ORM\Query\ResultSetMappingBuilder;
 use Doctrine\Persistence\ManagerRegistry;
 
 /**
@@ -37,4 +38,18 @@ class LocationRepository extends ServiceEntityRepository
     {
         return $this->findBy(['active' => true, 'availableForUsers' => true]);
     }
+
+    /**
+     * fetch location by name
+     *
+     * @return array|Location[]
+     */
+    public function findByName(string $name, string $lang): array
+    {
+        $rsm = new ResultSetMappingBuilder($this->getEntityManager());
+        $rsm->addRootEntityFromClassMetadata(Location::class);
+
+        $sql = "SELECT "
+
+    }
 }
diff --git a/src/Bundle/ChillMainBundle/Resources/public/module/pick-entity/index.js b/src/Bundle/ChillMainBundle/Resources/public/module/pick-entity/index.js
index 511d2126e..4e71e8568 100644
--- a/src/Bundle/ChillMainBundle/Resources/public/module/pick-entity/index.js
+++ b/src/Bundle/ChillMainBundle/Resources/public/module/pick-entity/index.js
@@ -6,6 +6,7 @@ import { appMessages } from 'ChillMainAssets/vuejs/PickEntity/i18n';
 const i18n = _createI18n(appMessages);
 
 let appsOnPage = new Map();
+let appsPerInput = new Map();
 
 function loadDynamicPicker(element) {
 
@@ -23,6 +24,8 @@ function loadDynamicPicker(element) {
                         null : [ JSON.parse(input.value) ]
                 )
         ;
+        console.log('picked at startup', picked);
+        console.log('input', input);
 
         if (!isMultiple) {
             if (input.value === '[]'){
@@ -78,13 +81,14 @@ function loadDynamicPicker(element) {
         .mount(el);
 
         appsOnPage.set(uniqId, app);
+        appsPerInput.set(input.name, app);
     });
 }
 
 
 document.addEventListener('show-hide-show', function(e) {
     loadDynamicPicker(e.detail.container)
-})
+});
 
 document.addEventListener('show-hide-hide', function(e) {
     console.log('hiding event caught')
@@ -95,7 +99,23 @@ document.addEventListener('show-hide-hide', function(e) {
             appsOnPage.delete(uniqId);
         }
     })
-})
+});
+
+document.addEventListener('pick-entity-type', function (e) {
+      console.log('pick entity event', e);
+      if (!appsPerInput.has(e.detail.name)) {
+          console.error('no app with this name');
+          return;
+      }
+      const app = appsPerInput.get(e.detail.name);
+      if (e.detail.action === 'add') {
+          app.addNewEntity(e.detail.entity);
+      } else if (e.detail.action === 'remove') {
+        app.removeEntity(e.detail.entity);
+      } else {
+          console.error('action not supported: '+e.detail.action);
+      }
+});
 
 document.addEventListener('DOMContentLoaded', function(e) {
     loadDynamicPicker(document)
diff --git a/src/Bundle/ChillMainBundle/Resources/views/Form/fields.html.twig b/src/Bundle/ChillMainBundle/Resources/views/Form/fields.html.twig
index ded9ff83d..212b4fbd2 100644
--- a/src/Bundle/ChillMainBundle/Resources/views/Form/fields.html.twig
+++ b/src/Bundle/ChillMainBundle/Resources/views/Form/fields.html.twig
@@ -231,6 +231,6 @@
 {% endblock %}
 
 {% block pick_entity_dynamic_widget %}
-    <input type="hidden" {{ block('widget_attributes') }} {% if value is not empty %}value="{{ value }}" {% endif %} data-input-uniqid="{{ form.vars['uniqid'] }}"/>
+    <input type="hidden" {{ block('widget_attributes') }} {% if value is not empty %}value="{{ value|escape('html_attr') }}" {% endif %} data-input-uniqid="{{ form.vars['uniqid'] }}"/>
     <div data-module="pick-dynamic" data-types="{{ form.vars['types']|json_encode }}" data-multiple="{{ form.vars['multiple'] }}" data-uniqid="{{ form.vars['uniqid'] }}"></div>
 {% endblock %}