diff --git a/openslides/agenda/static/js/agenda/base.js b/openslides/agenda/static/js/agenda/base.js
index a114268e7..38a4a1ced 100644
--- a/openslides/agenda/static/js/agenda/base.js
+++ b/openslides/agenda/static/js/agenda/base.js
@@ -113,13 +113,12 @@ angular.module('OpenSlidesApp.agenda', ['OpenSlidesApp.users'])
                 },
                 // override project function of jsDataModel factory
                 project: function (projectorId, tree) {
-                    var isProjectedId = this.isProjected(tree);
-                    if (isProjectedId > 0) {
-                        // Deactivate
-                        $http.post('/rest/core/projector/' + isProjectedId + '/clear_elements/');
-                    }
+                    var isProjectedIds = this.isProjected(tree);
+                    _.forEach(isProjectedIds, function (id) {
+                        $http.post('/rest/core/projector/' + id + '/clear_elements/');
+                    });
                     // Activate, if the projector_id is a new projector.
-                    if (isProjectedId != projectorId) {
+                    if (_.indexOf(isProjectedIds, projectorId) == -1) {
                         var name = tree ? 'agenda/item-list' : this.content_object.collection;
                         var id = tree ? this.id : this.content_object.id;
                         return $http.post(
@@ -160,13 +159,11 @@ angular.module('OpenSlidesApp.agenda', ['OpenSlidesApp.users'])
                 },
                 // project list of speakers
                 projectListOfSpeakers: function(projectorId) {
-                    var isProjectedId = this.isListOfSpeakersProjected();
-                    if (isProjectedId > 0) {
-                        // Deactivate
-                        $http.post('/rest/core/projector/' + isProjectedId + '/clear_elements/');
-                    }
-                    // Activate
-                    if (isProjectedId != projectorId) {
+                    var isProjectedIds = this.isListOfSpeakersProjected();
+                    _.forEach(isProjectedIds, function (id) {
+                        $http.post('/rest/core/projector/' + id + '/clear_elements/');
+                    });
+                    if (_.indexOf(isProjectedIds, projectorId) == -1) {
                         return $http.post(
                             '/rest/core/projector/' + projectorId + '/prune_elements/',
                             [{name: 'agenda/list-of-speakers', id: this.id}]
diff --git a/openslides/agenda/static/js/agenda/site.js b/openslides/agenda/static/js/agenda/site.js
index 4526f4850..c2406a58f 100644
--- a/openslides/agenda/static/js/agenda/site.js
+++ b/openslides/agenda/static/js/agenda/site.js
@@ -255,12 +255,11 @@ angular.module('OpenSlidesApp.agenda.site', [
         };
         // project agenda
         $scope.projectAgenda = function (projectorId, tree, id) {
-            var isAgendaProjectedId = $scope.isAgendaProjected($scope.mainListTree);
-            if (isAgendaProjectedId > 0) {
-                // Deactivate
-                $http.post('/rest/core/projector/' + isAgendaProjectedId + '/clear_elements/');
-            }
-            if (isAgendaProjectedId != projectorId) {
+            var isAgendaProjectedIds = $scope.isAgendaProjected($scope.mainListTree);
+            _.forEach(isAgendaProjectedIds, function (id) {
+                $http.post('/rest/core/projector/' + id + '/clear_elements/');
+            });
+            if (_.indexOf(isAgendaProjectedIds, projectorId) == -1) {
                 $http.post('/rest/core/projector/' + projectorId + '/prune_elements/',
                     [{name: 'agenda/item-list', tree: tree, id: id}]);
             }
@@ -568,12 +567,11 @@ angular.module('OpenSlidesApp.agenda.site', [
         // Project current list of speakers
         // same logic as in core/base.js
         $scope.projectCurrentLoS = function (projectorId) {
-            var isCurrentLoSProjectedId = $scope.isCurrentLoSProjected($scope.mainListTree);
-            if (isCurrentLoSProjectedId > 0) {
-                // Deactivate
-                $http.post('/rest/core/projector/' + isCurrentLoSProjectedId + '/clear_elements/');
-            }
-            if (isCurrentLoSProjectedId != projectorId) {
+            var isCurrentLoSProjectedIds = $scope.isCurrentLoSProjected($scope.mainListTree);
+            _.forEach(isCurrentLoSProjectedIds, function (id) {
+                $http.post('/rest/core/projector/' + id + '/clear_elements/');
+            });
+            if (_.indexOf(isCurrentLoSProjectedIds, projectorId) == -1) {
                 $http.post('/rest/core/projector/' + projectorId + '/prune_elements/',
                     [{name: 'agenda/current-list-of-speakers'}]);
             }
diff --git a/openslides/assignments/static/js/assignments/base.js b/openslides/assignments/static/js/assignments/base.js
index b727454b8..c362db260 100644
--- a/openslides/assignments/static/js/assignments/base.js
+++ b/openslides/assignments/static/js/assignments/base.js
@@ -268,11 +268,11 @@ angular.module('OpenSlidesApp.assignments', [])
                 },
                 // override project function of jsDataModel factory
                 project: function (projectorId, pollId) {
-                    var isProjectedId = this.isProjected(pollId);
-                    if (isProjectedId > 0) {
-                        $http.post('/rest/core/projector/' + isProjectedId + '/clear_elements/');
-                    }
-                    if (isProjectedId != projectorId) {
+                    var isProjectedIds = this.isProjected(pollId);
+                    _.forEach(isProjectedIds, function (id) {
+                        $http.post('/rest/core/projector/' + id + '/clear_elements/');
+                    });
+                    if (_.indexOf(isProjectedIds, projectorId) == -1) {
                         return $http.post(
                             '/rest/core/projector/' + projectorId + '/prune_elements/',
                             [{name: 'assignments/assignment', id: this.id, poll: pollId}]
diff --git a/openslides/core/static/js/core/base.js b/openslides/core/static/js/core/base.js
index ddb20759e..5e17c8720 100644
--- a/openslides/core/static/js/core/base.js
+++ b/openslides/core/static/js/core/base.js
@@ -391,11 +391,11 @@ angular.module('OpenSlidesApp.core', [
         BaseModel.prototype.project = function(projectorId) {
             // if this object is already projected on projectorId, delete this element from this projector
             var isProjectedIds = this.isProjected();
-            if (isProjectedIds.length > 0) {
-                $http.post('/rest/core/projector/' + isProjectedIds[0] + '/clear_elements/');
-            }
-            // if it was the same projector before, just delete it but not show again
-            if (isProjectedIds[0] != projectorId) {
+            _.forEach(isProjectedIds, function (id) {
+                $http.post('/rest/core/projector/' + id + '/clear_elements/');
+            });
+            // Show the element, if it was not projected before on the given projector
+            if (_.indexOf(isProjectedIds, projectorId) == -1) {
                 return $http.post(
                     '/rest/core/projector/' + projectorId + '/prune_elements/',
                     [{name: this.getResourceName(), id: this.id}]
diff --git a/openslides/mediafiles/static/js/mediafiles/site.js b/openslides/mediafiles/static/js/mediafiles/site.js
index 883f49809..ea33a45e8 100644
--- a/openslides/mediafiles/static/js/mediafiles/site.js
+++ b/openslides/mediafiles/static/js/mediafiles/site.js
@@ -156,11 +156,11 @@ angular.module('OpenSlidesApp.mediafiles.site', ['ngFileUpload', 'OpenSlidesApp.
         // ** PDF presentation functions **/
         // show document on projector
         $scope.showMediafile = function (projectorId, mediafile) {
-            var isProjectedId = mediafile.isProjected();
-            if (isProjectedId > 0) {
-                $http.post('/rest/core/projector/' + isProjectedId + '/clear_elements/');
-            }
-            if (isProjectedId != projectorId) {
+            var isProjectedIds = mediafile.isProjected();
+            _.forEach(isProjectedIds, function (id) {
+                $http.post('/rest/core/projector/' + id + '/clear_elements/');
+            });
+            if (_.indexOf(isProjectedIds, projectorId) == -1) {
                 var postUrl = '/rest/core/projector/' + projectorId + '/prune_elements/';
                 var data = [{
                         name: 'mediafiles/mediafile',