diff --git a/app/code/Magento/Catalog/Block/Adminhtml/Product/Helper/Form/Gallery/Content.php b/app/code/Magento/Catalog/Block/Adminhtml/Product/Helper/Form/Gallery/Content.php
index 9fb672b07b8d1..f61f9071155aa 100644
--- a/app/code/Magento/Catalog/Block/Adminhtml/Product/Helper/Form/Gallery/Content.php
+++ b/app/code/Magento/Catalog/Block/Adminhtml/Product/Helper/Form/Gallery/Content.php
@@ -122,21 +122,40 @@ public function getAddImagesButton()
      */
     public function getImagesJson()
     {
-        if (is_array($this->getElement()->getImages())) {
-            $value = $this->getElement()->getImages();
+        $value = $this->getElement()->getImages();
+        if (is_array($value) &&
+            array_key_exists('images', $value) &&
+            is_array($value['images']) &&
+            count($value['images'])
+        ) {
             $directory = $this->_filesystem->getDirectoryRead(DirectoryList::MEDIA);
-            if (is_array($value['images']) && count($value['images']) > 0) {
-                foreach ($value['images'] as &$image) {
-                    $image['url'] = $this->_mediaConfig->getMediaUrl($image['file']);
-                    $fileHandler = $directory->stat($this->_mediaConfig->getMediaPath($image['file']));
-                    $image['size'] = $fileHandler['size'];
-                }
-                return $this->_jsonEncoder->encode($value['images']);
+            $images = $this->sortImagesByPosition($value['images']);
+            foreach ($images as &$image) {
+                $image['url'] = $this->_mediaConfig->getMediaUrl($image['file']);
+                $fileHandler = $directory->stat($this->_mediaConfig->getMediaPath($image['file']));
+                $image['size'] = $fileHandler['size'];
             }
+            return $this->_jsonEncoder->encode($images);
         }
         return '[]';
     }
 
+    /**
+     * Sort images array by position key
+     *
+     * @param array $images
+     * @return array
+     */
+    private function sortImagesByPosition($images)
+    {
+        if (is_array($images)) {
+            usort($images, function ($imageA, $imageB) {
+                return ($imageA['position'] < $imageB['position']) ? -1 : 1;
+            });
+        }
+        return $images;
+    }
+
     /**
      * @return string
      */
diff --git a/app/code/Magento/Catalog/Test/Unit/Block/Adminhtml/Product/Helper/Form/Gallery/ContentTest.php b/app/code/Magento/Catalog/Test/Unit/Block/Adminhtml/Product/Helper/Form/Gallery/ContentTest.php
index f7d1137407ff3..72a25933efa0b 100644
--- a/app/code/Magento/Catalog/Test/Unit/Block/Adminhtml/Product/Helper/Form/Gallery/ContentTest.php
+++ b/app/code/Magento/Catalog/Test/Unit/Block/Adminhtml/Product/Helper/Form/Gallery/ContentTest.php
@@ -82,37 +82,59 @@ public function testGetImagesJson()
             ['file_1.jpg', 'catalog/product/image_1.jpg'],
             ['file_2.jpg', 'catalog/product/image_2.jpg']
         ];
-        // @codingStandardsIgnoreStart
-        $encodedString = '[{"value_id":"1","file":"image_1.jpg","media_type":"image","url":"http:\/\/magento2.dev\/pub\/media\/catalog\/product\/image_1.jpg","size":879394},{"value_id":"2","file":"image_2.jpg","media_type":"image","url":"http:\/\/magento2.dev\/pub\/media\/catalog\/product\/image`_2.jpg","size":399659}]';
-        // @codingStandardsIgnoreEnd
+
+        $sizeMap = [
+            ['catalog/product/image_1.jpg', ['size' => 399659]],
+            ['catalog/product/image_2.jpg', ['size' => 879394]]
+        ];
+
+        $imagesResult = [
+            [
+                'value_id' => '2',
+                'file' => 'file_2.jpg',
+                'media_type' => 'image',
+                'position' => '0',
+                'url' => 'url_to_the_image/image_2.jpg',
+                'size' => 879394
+            ],
+            [
+                'value_id' => '1',
+                'file' => 'file_1.jpg',
+                'media_type' => 'image',
+                'position' => '1',
+                'url' => 'url_to_the_image/image_1.jpg',
+                'size' => 399659
+            ]
+        ];
+
         $images = [
             'images' => [
                 [
                     'value_id' => '1',
                     'file' => 'file_1.jpg',
                     'media_type' => 'image',
+                    'position' => '1'
                 ] ,
                 [
                     'value_id' => '2',
                     'file' => 'file_2.jpg',
                     'media_type' => 'image',
+                    'position' => '0'
                 ]
             ]
         ];
-        $firstStat = ['size' => 879394];
-        $secondStat = ['size' => 399659];
+
         $this->content->setElement($this->galleryMock);
-        $this->galleryMock->expects($this->any())->method('getImages')->willReturn($images);
+        $this->galleryMock->expects($this->once())->method('getImages')->willReturn($images);
         $this->fileSystemMock->expects($this->once())->method('getDirectoryRead')->willReturn($this->readMock);
 
         $this->mediaConfigMock->expects($this->any())->method('getMediaUrl')->willReturnMap($url);
-        $this->mediaConfigMock->expects($this->any())->method('getMediaPath')->willReturn($mediaPath);
+        $this->mediaConfigMock->expects($this->any())->method('getMediaPath')->willReturnMap($mediaPath);
 
-        $this->readMock->expects($this->at(0))->method('stat')->willReturn($firstStat);
-        $this->readMock->expects($this->at(1))->method('stat')->willReturn($secondStat);
-        $this->jsonEncoderMock->expects($this->once())->method('encode')->willReturn($encodedString);
+        $this->readMock->expects($this->any())->method('stat')->willReturnMap($sizeMap);
+        $this->jsonEncoderMock->expects($this->once())->method('encode')->willReturnCallback('json_encode');
 
-        $this->assertSame($encodedString, $this->content->getImagesJson());
+        $this->assertSame(json_encode($imagesResult), $this->content->getImagesJson());
     }
 
     public function testGetImagesJsonWithoutImages()
diff --git a/app/code/Magento/CatalogImportExport/Model/Import/Product.php b/app/code/Magento/CatalogImportExport/Model/Import/Product.php
index b56a03da0f3b5..03c2f3f4f511a 100644
--- a/app/code/Magento/CatalogImportExport/Model/Import/Product.php
+++ b/app/code/Magento/CatalogImportExport/Model/Import/Product.php
@@ -1270,7 +1270,7 @@ protected function _saveProductCategories(array $categoriesData)
                 );
             }
             if ($categoriesIn) {
-                $this->_connection->insertOnDuplicate($tableName, $categoriesIn, ['position']);
+                $this->_connection->insertOnDuplicate($tableName, $categoriesIn, ['product_id', 'category_id']);
             }
         }
         return $this;
diff --git a/app/code/Magento/Newsletter/Block/Adminhtml/Queue/Edit.php b/app/code/Magento/Newsletter/Block/Adminhtml/Queue/Edit.php
index dff671f15f0c4..f71b1f76d7ff4 100644
--- a/app/code/Magento/Newsletter/Block/Adminhtml/Queue/Edit.php
+++ b/app/code/Magento/Newsletter/Block/Adminhtml/Queue/Edit.php
@@ -161,7 +161,12 @@ protected function _prepareLayout()
      */
     public function getPreviewUrl()
     {
-        return $this->getUrl('*/*/preview');
+        if ($this->getTemplateId()) {
+            $params = ['template_id' => $this->getTemplateId()];
+        } else {
+            $params = ['id' => $this->getRequest()->getParam('id')];
+        }
+        return $this->getUrl('*/*/preview', $params);
     }
 
     /**
diff --git a/app/code/Magento/Newsletter/Block/Adminhtml/Queue/Preview/Form.php b/app/code/Magento/Newsletter/Block/Adminhtml/Queue/Preview/Form.php
index bf237fb9787de..0e4a69d1050f8 100644
--- a/app/code/Magento/Newsletter/Block/Adminhtml/Queue/Preview/Form.php
+++ b/app/code/Magento/Newsletter/Block/Adminhtml/Queue/Preview/Form.php
@@ -35,6 +35,10 @@ protected function _prepareForm()
         if ($data = $this->getFormData()) {
             $mapper = ['preview_store_id' => 'store_id'];
 
+            if (empty($data['id']) && !empty($data['text'])) {
+                $this->_backendSession->setPreviewData($data);
+            }
+
             foreach ($data as $key => $value) {
                 if (array_key_exists($key, $mapper)) {
                     $name = $mapper[$key];
diff --git a/app/code/Magento/Newsletter/Block/Adminhtml/Template/Edit.php b/app/code/Magento/Newsletter/Block/Adminhtml/Template/Edit.php
index 2bbd61bf47bd0..03297c9c45181 100644
--- a/app/code/Magento/Newsletter/Block/Adminhtml/Template/Edit.php
+++ b/app/code/Magento/Newsletter/Block/Adminhtml/Template/Edit.php
@@ -238,7 +238,7 @@ public function getSaveUrl()
      */
     public function getPreviewUrl()
     {
-        return $this->getUrl('*/*/preview');
+        return $this->getUrl('*/*/preview', ['id' => $this->getRequest()->getParam('id')]);
     }
 
     /**
diff --git a/app/code/Magento/Newsletter/Block/Adminhtml/Template/Preview.php b/app/code/Magento/Newsletter/Block/Adminhtml/Template/Preview.php
index 4bce98adb6ebb..0a415fe7c2024 100644
--- a/app/code/Magento/Newsletter/Block/Adminhtml/Template/Preview.php
+++ b/app/code/Magento/Newsletter/Block/Adminhtml/Template/Preview.php
@@ -58,9 +58,11 @@ protected function _toHtml()
         if ($id = (int)$this->getRequest()->getParam('id')) {
             $this->loadTemplate($template, $id);
         } else {
-            $template->setTemplateType($this->getRequest()->getParam('type'));
-            $template->setTemplateText($this->getRequest()->getParam('text'));
-            $template->setTemplateStyles($this->getRequest()->getParam('styles'));
+            $previewData = $this->getPreviewData();
+
+            $template->setTemplateType($previewData['type']);
+            $template->setTemplateText($previewData['text']);
+            $template->setTemplateStyles($previewData['styles']);
         }
 
         \Magento\Framework\Profiler::start($this->profilerName);
@@ -88,6 +90,32 @@ protected function _toHtml()
         return $templateProcessed;
     }
 
+    /**
+     * Return template preview data
+     *
+     * @return array
+     */
+    private function getPreviewData()
+    {
+        $previewData = [];
+        $previewParams = ['type', 'text', 'styles'];
+
+        $sessionData = [];
+        if ($this->_backendSession->hasPreviewData()) {
+            $sessionData = $this->_backendSession->getPreviewData();
+        }
+
+        foreach ($previewParams as $param) {
+            if (isset($sessionData[$param])) {
+                $previewData[$param] = $sessionData[$param];
+            } else {
+                $previewData[$param] = $this->getRequest()->getParam($param);
+            }
+        }
+
+        return $previewData;
+    }
+
     /**
      * Get Store Id from request or default
      *
diff --git a/app/code/Magento/Newsletter/Block/Adminhtml/Template/Preview/Form.php b/app/code/Magento/Newsletter/Block/Adminhtml/Template/Preview/Form.php
index efc15663d462b..ac6d569d69a88 100644
--- a/app/code/Magento/Newsletter/Block/Adminhtml/Template/Preview/Form.php
+++ b/app/code/Magento/Newsletter/Block/Adminhtml/Template/Preview/Form.php
@@ -35,6 +35,10 @@ protected function _prepareForm()
         if ($data = $this->getFormData()) {
             $mapper = ['preview_store_id' => 'store_id'];
 
+            if (empty($data['id']) && !empty($data['text'])) {
+                $this->_backendSession->setPreviewData($data);
+            }
+
             foreach ($data as $key => $value) {
                 if (array_key_exists($key, $mapper)) {
                     $name = $mapper[$key];
diff --git a/app/code/Magento/Newsletter/Controller/Adminhtml/Queue/Preview.php b/app/code/Magento/Newsletter/Controller/Adminhtml/Queue/Preview.php
index 64d33a0fda3a9..a11d1abc82b9b 100644
--- a/app/code/Magento/Newsletter/Controller/Adminhtml/Queue/Preview.php
+++ b/app/code/Magento/Newsletter/Controller/Adminhtml/Queue/Preview.php
@@ -17,7 +17,11 @@ public function execute()
     {
         $this->_view->loadLayout();
         $data = $this->getRequest()->getParams();
-        if (empty($data) || !isset($data['id'])) {
+
+        $isEmptyRequestData = empty($data) || !isset($data['id']);
+        $isEmptyPreviewData = !$this->_getSession()->hasPreviewData() || empty($this->_getSession()->getPreviewData());
+        
+        if ($isEmptyRequestData && $isEmptyPreviewData) {
             $this->_forward('noroute');
             return;
         }
diff --git a/app/code/Magento/Newsletter/Controller/Adminhtml/Queue/Save.php b/app/code/Magento/Newsletter/Controller/Adminhtml/Queue/Save.php
index a96cd34edb85d..4acef96088aff 100644
--- a/app/code/Magento/Newsletter/Controller/Adminhtml/Queue/Save.php
+++ b/app/code/Magento/Newsletter/Controller/Adminhtml/Queue/Save.php
@@ -82,6 +82,7 @@ public function execute()
 
             $this->messageManager->addSuccess(__('You saved the newsletter queue.'));
             $this->_getSession()->setFormData(false);
+            $this->_getSession()->unsPreviewData();
 
             $this->_redirect('*/*');
         } catch (\Magento\Framework\Exception\LocalizedException $e) {
diff --git a/app/code/Magento/Newsletter/Controller/Adminhtml/Template/Preview.php b/app/code/Magento/Newsletter/Controller/Adminhtml/Template/Preview.php
index e01897d71d197..80579ddb49395 100644
--- a/app/code/Magento/Newsletter/Controller/Adminhtml/Template/Preview.php
+++ b/app/code/Magento/Newsletter/Controller/Adminhtml/Template/Preview.php
@@ -18,7 +18,10 @@ public function execute()
         $this->_view->loadLayout();
 
         $data = $this->getRequest()->getParams();
-        if (empty($data) || !isset($data['id'])) {
+        $isEmptyRequestData = empty($data) || !isset($data['id']);
+        $isEmptyPreviewData = !$this->_getSession()->hasPreviewData() || empty($this->_getSession()->getPreviewData());
+        
+        if ($isEmptyRequestData && $isEmptyPreviewData) {
             $this->_forward('noroute');
             return $this;
         }
diff --git a/app/code/Magento/Newsletter/Controller/Adminhtml/Template/Save.php b/app/code/Magento/Newsletter/Controller/Adminhtml/Template/Save.php
index 9aeb187e99019..ee09d6da776bc 100644
--- a/app/code/Magento/Newsletter/Controller/Adminhtml/Template/Save.php
+++ b/app/code/Magento/Newsletter/Controller/Adminhtml/Template/Save.php
@@ -63,7 +63,7 @@ public function execute()
 
             $this->messageManager->addSuccess(__('The newsletter template has been saved.'));
             $this->_getSession()->setFormData(false);
-
+            $this->_getSession()->unsPreviewData();
             $this->_redirect('*/template');
             return;
         } catch (LocalizedException $e) {
diff --git a/app/code/Magento/Newsletter/Test/Unit/Block/Adminhtml/Queue/PreviewTest.php b/app/code/Magento/Newsletter/Test/Unit/Block/Adminhtml/Queue/PreviewTest.php
index dae38205e1d72..ad90c5a6d9159 100644
--- a/app/code/Magento/Newsletter/Test/Unit/Block/Adminhtml/Queue/PreviewTest.php
+++ b/app/code/Magento/Newsletter/Test/Unit/Block/Adminhtml/Queue/PreviewTest.php
@@ -62,6 +62,12 @@ protected function setUp()
         $appState = $this->getMock('Magento\Framework\App\State', [], [], '', false);
         $context->expects($this->once())->method('getAppState')->will($this->returnValue($appState));
 
+        $backendSession = $this->getMockBuilder('Magento\Backend\Model\Session')
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        $context->expects($this->once())->method('getBackendSession')->willReturn($backendSession);
+
         $templateFactory = $this->getMock('Magento\Newsletter\Model\TemplateFactory', ['create'], [], '', false);
         $this->template = $this->getMock('Magento\Newsletter\Model\Template', [], [], '', false);
         $templateFactory->expects($this->once())->method('create')->will($this->returnValue($this->template));
diff --git a/app/code/Magento/Newsletter/view/adminhtml/layout/newsletter_queue_preview.xml b/app/code/Magento/Newsletter/view/adminhtml/layout/newsletter_queue_preview.xml
index 9081bbd72b2d6..13c329b2f022c 100644
--- a/app/code/Magento/Newsletter/view/adminhtml/layout/newsletter_queue_preview.xml
+++ b/app/code/Magento/Newsletter/view/adminhtml/layout/newsletter_queue_preview.xml
@@ -10,6 +10,7 @@
         <attribute name="id" value="html-body"/>
         <attribute name="class" value="preview-window"/>
         <referenceContainer name="backend.page" remove="true"/>
+        <referenceContainer name="menu.wrapper" remove="true"/>
         <referenceContainer name="root">
             <block name="preview.page.content" class="Magento\Backend\Block\Page" template="Magento_Newsletter::preview/iframeswitcher.phtml">
                 <block class="Magento\Newsletter\Block\Adminhtml\Queue\Preview\Form" name="preview_form"/>
diff --git a/app/code/Magento/Newsletter/view/adminhtml/layout/newsletter_template_preview.xml b/app/code/Magento/Newsletter/view/adminhtml/layout/newsletter_template_preview.xml
index fb7088093ae52..81898079f46e6 100644
--- a/app/code/Magento/Newsletter/view/adminhtml/layout/newsletter_template_preview.xml
+++ b/app/code/Magento/Newsletter/view/adminhtml/layout/newsletter_template_preview.xml
@@ -10,6 +10,7 @@
         <attribute name="id" value="html-body"/>
         <attribute name="class" value="preview-window"/>
         <referenceContainer name="backend.page" remove="true"/>
+        <referenceContainer name="menu.wrapper" remove="true"/>
         <referenceContainer name="root">
             <block name="preview.page.content" class="Magento\Backend\Block\Page" template="Magento_Newsletter::preview/iframeswitcher.phtml">
                 <block class="Magento\Newsletter\Block\Adminhtml\Template\Preview\Form" name="preview_form"/>
diff --git a/app/code/Magento/Newsletter/view/adminhtml/templates/preview/iframeswitcher.phtml b/app/code/Magento/Newsletter/view/adminhtml/templates/preview/iframeswitcher.phtml
index ef1d0593a1a6b..aa5679047a593 100644
--- a/app/code/Magento/Newsletter/view/adminhtml/templates/preview/iframeswitcher.phtml
+++ b/app/code/Magento/Newsletter/view/adminhtml/templates/preview/iframeswitcher.phtml
@@ -42,8 +42,8 @@ function unBlockPreview() {
     jQuery('body').trigger('hideLoadingPopup');
 }
 
-Event.observe(window, 'load', preview);
-Event.observe(previewIframe, 'load', unBlockPreview);
+jQuery(document).ready(preview);
+jQuery(previewIframe).ready(unBlockPreview);
 
 jQuery("#preview_iframe").load(function() {
     jQuery(this).height(jQuery(this).contents().find("html").height() );
diff --git a/app/code/Magento/ProductVideo/view/frontend/web/js/fotorama-add-video-events.js b/app/code/Magento/ProductVideo/view/frontend/web/js/fotorama-add-video-events.js
index 7975efc95180b..0b149e37a0716 100644
--- a/app/code/Magento/ProductVideo/view/frontend/web/js/fotorama-add-video-events.js
+++ b/app/code/Magento/ProductVideo/view/frontend/web/js/fotorama-add-video-events.js
@@ -249,11 +249,7 @@ define([
                     tmpVideoData.videoUrl = tmpInputData.videoUrl;
                 }
 
-                if (tmpVideoData.isBase) {
-                    videoData.unshift(tmpVideoData);
-                } else {
-                    videoData.push(tmpVideoData);
-                }
+                videoData.push(tmpVideoData);
             }
 
             return videoData;
diff --git a/app/code/Magento/Swatches/view/frontend/web/js/swatch-renderer.js b/app/code/Magento/Swatches/view/frontend/web/js/swatch-renderer.js
index 326cbd7e43c5d..5135493c06494 100644
--- a/app/code/Magento/Swatches/view/frontend/web/js/swatch-renderer.js
+++ b/app/code/Magento/Swatches/view/frontend/web/js/swatch-renderer.js
@@ -184,6 +184,9 @@ define([
             // Callback url for media
             mediaCallback: '',
 
+            // Local media cache
+            mediaCache: {},
+
             // Cache for BaseProduct images. Needed when option unset
             mediaGalleryInitial: [{}],
 
@@ -718,7 +721,22 @@ define([
                 $this = $widget.element,
                 attributes = {},
                 productId = 0,
-                additional;
+                mediaCallData,
+                mediaCacheKey,
+
+                /**
+                 * Processes product media data
+                 *
+                 * @param {Object} data
+                 * @returns void
+                 */
+                mediaSuccessCallback = function (data) {
+                    if (!(mediaCacheKey in $widget.options.mediaCache)) {
+                        $widget.options.mediaCache[mediaCacheKey] = data;
+                    }
+                    $widget._ProductMediaCallback($this, data);
+                    $widget._DisableProductMediaLoader($this);
+                };
 
             if (!$widget.options.mediaCallback) {
                 return;
@@ -739,24 +757,28 @@ define([
                     .find('.price-box.price-final_price').attr('data-product-id');
             }
 
-            additional = $.parseQuery();
-
-            $widget._XhrKiller();
-            $widget._EnableProductMediaLoader($this);
-            $widget.xhr = $.post(
-                $widget.options.mediaCallback, {
-                    'product_id': productId,
-                    attributes: attributes,
-                    isAjax: true,
-                    additional: additional
-                }, function (data) {
-                    $widget._ProductMediaCallback($this, data);
-                    $widget._DisableProductMediaLoader($this);
-                },
-                'json'
-            ).done(function () {
+            mediaCallData = {
+                'product_id': productId,
+                'attributes': attributes,
+                'additional': $.parseQuery()
+            };
+            mediaCacheKey = JSON.stringify(mediaCallData);
+
+            if (mediaCacheKey in $widget.options.mediaCache) {
+                mediaSuccessCallback($widget.options.mediaCache[mediaCacheKey]);
+            } else {
+                mediaCallData.isAjax = true;
+                $widget._XhrKiller();
+                $widget._EnableProductMediaLoader($this);
+                $widget.xhr = $.post(
+                    $widget.options.mediaCallback,
+                    mediaCallData,
+                    mediaSuccessCallback,
+                    'json'
+                ).done(function () {
                     $widget._XhrKiller();
                 });
+            }
         },
 
         /**
@@ -820,32 +842,30 @@ define([
                     return e.hasOwnProperty('large') && e.hasOwnProperty('medium') && e.hasOwnProperty('small');
                 };
 
-            if (_.size($widget) < 1) {
+            if (_.size($widget) < 1 || !support(response)) {
                 this.updateBaseImage(this.options.mediaGalleryInitial, $main, isProductViewExist);
 
                 return;
             }
 
-            if (support(response)) {
-                images.push({
-                    full: response.large,
-                    img: response.medium,
-                    thumb: response.small,
-                    isMain: true
-                });
+            images.push({
+                full: response.large,
+                img: response.medium,
+                thumb: response.small,
+                isMain: true
+            });
 
-                if (response.hasOwnProperty('gallery')) {
-                    $.each(response.gallery, function () {
-                        if (!support(this) || response.large === this.large) {
-                            return;
-                        }
-                        images.push({
-                            full: this.large,
-                            img: this.medium,
-                            thumb: this.small
-                        });
+            if (response.hasOwnProperty('gallery')) {
+                $.each(response.gallery, function () {
+                    if (!support(this) || response.large === this.large) {
+                        return;
+                    }
+                    images.push({
+                        full: this.large,
+                        img: this.medium,
+                        thumb: this.small
                     });
-                }
+                });
             }
 
             this.updateBaseImage(images, $main, isProductViewExist);
@@ -882,11 +902,9 @@ define([
                 gallery = context.find(this.options.mediaGallerySelector).data('gallery'),
                 item;
 
-            if (images) {
-                imagesToUpdate = this._setImageType($.extend(true, [], images));
-            }
-
             if (isProductViewExist) {
+                imagesToUpdate = images.length ? this._setImageType($.extend(true, [], images)) : [];
+
                 if (this.options.onlyMainImg) {
                     updateImg = imagesToUpdate.filter(function (img) {
                         return img.isMain;
diff --git a/app/code/Magento/Wishlist/view/frontend/web/js/add-to-wishlist.js b/app/code/Magento/Wishlist/view/frontend/web/js/add-to-wishlist.js
index 600c38ace28c4..d442c7e878a24 100644
--- a/app/code/Magento/Wishlist/view/frontend/web/js/add-to-wishlist.js
+++ b/app/code/Magento/Wishlist/view/frontend/web/js/add-to-wishlist.js
@@ -23,6 +23,7 @@ define([
         },
         _bind: function() {
             var options = this.options,
+                dataUpdateFunc = '_updateWishlistData',
                 changeCustomOption = 'change ' + options.customOptionsInfo,
                 changeQty = 'change ' + options.qtyInfo,
                 events = {};
@@ -35,12 +36,14 @@ define([
                 options.productType = [];
             }
 
-            events[changeCustomOption] = '_updateWishlistData';
-            events[changeQty] = '_updateWishlistData';
-            options.productType.forEach(function (type) {
-                events['change ' + options[type + 'Info']] = '_updateWishlistData';
-            });
+            events[changeCustomOption] = dataUpdateFunc;
+            events[changeQty] = dataUpdateFunc;
 
+            for (var key in options.productType) {
+                if (options.productType.hasOwnProperty(key) && options.productType[key] + 'Info' in options) {
+                    events['change ' + options[options.productType[key] + 'Info']] = dataUpdateFunc;
+                }
+            }
             this._on(events);
         },
         _updateWishlistData: function(event) {
diff --git a/dev/tests/functional/tests/app/Magento/Newsletter/Test/Block/Adminhtml/Template/FormPageActions.php b/dev/tests/functional/tests/app/Magento/Newsletter/Test/Block/Adminhtml/Template/FormPageActions.php
index c544a86f454ad..ff8214f9034b8 100644
--- a/dev/tests/functional/tests/app/Magento/Newsletter/Test/Block/Adminhtml/Template/FormPageActions.php
+++ b/dev/tests/functional/tests/app/Magento/Newsletter/Test/Block/Adminhtml/Template/FormPageActions.php
@@ -17,9 +17,26 @@
 class FormPageActions extends AbstractFormPageActions
 {
     /**
-     * "Save" button
+     * "Save Template" button
      *
      * @var string
      */
     protected $saveButton = "[data-ui-id='page-actions-toolbar-save-button']";
+
+    /**
+     * "Preview Template" button
+     *
+     * @var string
+     */
+    private $previewButton = "[data-role='template-preview']";
+
+    /**
+     * Click preview button on form page
+     *
+     * @return void
+     */
+    public function clickPreview()
+    {
+        $this->_rootElement->find($this->previewButton)->click();
+    }
 }
diff --git a/dev/tests/functional/tests/app/Magento/Newsletter/Test/TestCase/PreviewNewsletterTemplateEntityTest.php b/dev/tests/functional/tests/app/Magento/Newsletter/Test/TestCase/PreviewNewsletterTemplateEntityTest.php
new file mode 100644
index 0000000000000..bd30c443ca0c1
--- /dev/null
+++ b/dev/tests/functional/tests/app/Magento/Newsletter/Test/TestCase/PreviewNewsletterTemplateEntityTest.php
@@ -0,0 +1,87 @@
+<?php
+/**
+ * Copyright © 2016 Magento. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+
+namespace Magento\Newsletter\Test\TestCase;
+
+use Magento\Newsletter\Test\Fixture\Template;
+use Magento\Newsletter\Test\Page\Adminhtml\TemplateIndex;
+use Magento\Newsletter\Test\Page\Adminhtml\TemplateNewIndex;
+use Magento\Mtf\TestCase\Injectable;
+
+/**
+ * Newsletter Templates Preview on Newsletter Template page
+ *
+ * Test Flow:
+ * Preconditions:
+ * 1. Create newsletter
+ *
+ * Steps:
+ * 1. Open Backend
+ * 2. Go to "Marketing" -> "Newsletter Template"
+ * 3. Find created template in grid and open it
+ * 4. Click "Preview Template" button at the top of the page
+ * 5. Perform all assertions
+ *
+ * @group Newsletters_(MX)
+ * @ZephyrId MAGETWO-51979
+ */
+class PreviewNewsletterTemplateEntityTest extends Injectable
+{
+    /* tags */
+    const MVP = 'yes';
+    const DOMAIN = 'MX';
+    /* end tags */
+
+    /**
+     * Page with newsletter template grid
+     *
+     * @var TemplateIndex
+     */
+    protected $templateIndex;
+
+    /**
+     * Page for create newsletter template
+     *
+     * @var TemplateNewIndex
+     */
+    protected $templateNewIndex;
+
+    /**
+     * Inject newsletter page
+     *
+     * @param TemplateIndex $templateIndex
+     * @param TemplateNewIndex $templateNewIndex
+     * @return void
+     */
+    public function __inject(
+        TemplateIndex $templateIndex,
+        TemplateNewIndex $templateNewIndex
+    ) {
+        $this->templateIndex = $templateIndex;
+        $this->templateNewIndex = $templateNewIndex;
+    }
+
+    /**
+     * Action for Newsletter Template
+     *
+     * @param Template $newsletter
+     * @return void
+     */
+    public function test(Template $newsletter)
+    {
+        // Preconditions
+        $newsletter->persist();
+
+        // Steps
+        // 1. Open Backend
+        // 2. Go to "Marketing" -> "Newsletter Template"
+        $this->templateIndex->open();
+        // 3. Find created template in grid and open it
+        $this->templateIndex->getNewsletterTemplateGrid()->searchAndOpen(['code' => $newsletter->getCode()]);
+        // 4. Click "Preview Template" button at the top of the page
+        $this->templateNewIndex->getFormPageActions()->clickPreview();
+    }
+}
diff --git a/dev/tests/functional/tests/app/Magento/Newsletter/Test/TestCase/PreviewNewsletterTemplateEntityTest.xml b/dev/tests/functional/tests/app/Magento/Newsletter/Test/TestCase/PreviewNewsletterTemplateEntityTest.xml
new file mode 100644
index 0000000000000..13b499fca5e3c
--- /dev/null
+++ b/dev/tests/functional/tests/app/Magento/Newsletter/Test/TestCase/PreviewNewsletterTemplateEntityTest.xml
@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+/**
+ * Copyright © 2016 Magento. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+ -->
+<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../../../../../../vendor/magento/mtf/etc/variations.xsd">
+    <testCase name="Magento\Newsletter\Test\TestCase\PreviewNewsletterTemplateEntityTest" summary="Newsletter Template Preview" ticketId="MAGETWO-51979">
+        <variation name="PreviewNewsletterTemplateEntityTestVariation1">
+            <data name="newsletter/dataset" xsi:type="string">default</data>
+            <constraint name="Magento\Newsletter\Test\Constraint\AssertNewsletterPreview" />
+        </variation>
+    </testCase>
+</config>
diff --git a/dev/tests/integration/testsuite/Magento/CatalogImportExport/Model/Import/ProductTest.php b/dev/tests/integration/testsuite/Magento/CatalogImportExport/Model/Import/ProductTest.php
index 499fdf32045b0..3be0fa114309c 100644
--- a/dev/tests/integration/testsuite/Magento/CatalogImportExport/Model/Import/ProductTest.php
+++ b/dev/tests/integration/testsuite/Magento/CatalogImportExport/Model/Import/ProductTest.php
@@ -14,6 +14,8 @@
  */
 namespace Magento\CatalogImportExport\Model\Import;
 
+use Magento\Catalog\Api\ProductRepositoryInterface;
+use Magento\Catalog\Model\Category;
 use Magento\Framework\App\Bootstrap;
 use Magento\Framework\App\Filesystem\DirectoryList;
 use Magento\ImportExport\Model\Import;
@@ -887,6 +889,70 @@ public function testProductCategories($fixture, $separator)
         $this->assertTrue(count($categories) == 2);
     }
 
+    /**
+     * @magentoAppArea adminhtml
+     * @magentoDbIsolation enabled
+     * @magentoAppIsolation enabled
+     * @magentoDataFixture Magento/Catalog/_files/multiple_products.php
+     * @magentoDataFixture Magento/Catalog/_files/category.php
+     */
+    public function testProductPositionInCategory()
+    {
+        /* @var \Magento\Catalog\Model\ResourceModel\Category\Collection $collection */
+        $collection = $this->objectManager->create(\Magento\Catalog\Model\ResourceModel\Category\Collection::class);
+        $collection->addNameToResult()->load();
+        /** @var Category $category */
+        $category = $collection->getItemByColumnValue('name', 'Category 1');
+
+        /** @var ProductRepositoryInterface $productRepository */
+        $productRepository = $this->objectManager->create(ProductRepositoryInterface::class);
+
+        $categoryProducts = [];
+        $i = 51;
+        foreach (['simple1', 'simple2', 'simple3'] as $sku) {
+            $categoryProducts[$productRepository->get($sku)->getId()] = $i++;
+        }
+        $category->setPostedProducts($categoryProducts);
+        $category->save();
+
+        $filesystem = \Magento\TestFramework\Helper\Bootstrap::getObjectManager()->create(
+            \Magento\Framework\Filesystem::class
+        );
+
+        $directory = $filesystem->getDirectoryWrite(DirectoryList::ROOT);
+        $source = $this->objectManager->create(
+            \Magento\ImportExport\Model\Import\Source\Csv::class,
+            [
+                'file' => __DIR__ . '/_files/products_to_import.csv',
+                'directory' => $directory
+            ]
+        );
+        $errors = $this->_model->setSource(
+            $source
+        )->setParameters(
+            [
+                'behavior' => \Magento\ImportExport\Model\Import::BEHAVIOR_APPEND,
+                'entity' => 'catalog_product'
+            ]
+        )->validateData();
+
+        $this->assertTrue($errors->getErrorsCount() == 0);
+        $this->_model->importData();
+
+        /** @var \Magento\Framework\App\ResourceConnection $resourceConnection */
+        $resourceConnection = \Magento\TestFramework\Helper\Bootstrap::getObjectManager()->get(
+            \Magento\Framework\App\ResourceConnection::class
+        );
+        $tableName = $resourceConnection->getTableName('catalog_category_product');
+        $select = $resourceConnection->getConnection()->select()->from($tableName)
+            ->where('category_id = ?', $category->getId());
+        $items = $resourceConnection->getConnection()->fetchAll($select);
+        $this->assertCount(3, $items);
+        foreach ($items as $item) {
+            $this->assertGreaterThan(50, $item['position']);
+        }
+    }
+
     /**
      * @return array
      */
diff --git a/dev/tests/integration/testsuite/Magento/CatalogImportExport/Model/Import/_files/products_to_import.csv b/dev/tests/integration/testsuite/Magento/CatalogImportExport/Model/Import/_files/products_to_import.csv
index a107fdff250ec..383a9414c9e22 100644
--- a/dev/tests/integration/testsuite/Magento/CatalogImportExport/Model/Import/_files/products_to_import.csv
+++ b/dev/tests/integration/testsuite/Magento/CatalogImportExport/Model/Import/_files/products_to_import.csv
@@ -1,4 +1,4 @@
-sku,product_type,store_view_code,name,price,attribute_set_code
-simple1,simple,,"simple 1",25,Default
-simple2,simple,,"simple 2",34,Default
-simple3,simple,,"simple 3",58,Default
+sku,product_type,store_view_code,name,price,attribute_set_code,categories
+simple1,simple,,"simple 1",25,Default,"Default Category/Category 1"
+simple2,simple,,"simple 2",34,Default,"Default Category/Category 1"
+simple3,simple,,"simple 3",58,Default,"Default Category/Category 1"
diff --git a/lib/web/mage/gallery/gallery.js b/lib/web/mage/gallery/gallery.js
index d2f13455992a2..11ee24f6816dc 100644
--- a/lib/web/mage/gallery/gallery.js
+++ b/lib/web/mage/gallery/gallery.js
@@ -15,28 +15,20 @@ define([
     'use strict';
 
     /**
-     * Set main item first in order.
-     * @param {Array.<Object>} data - Set of gallery items to update.
+     * Retrieves index if the main item.
+     * @param {Array.<Object>} data - Set of gallery items.
      */
-    var pushMainFirst = function (data) {
+    var getMainImageIndex = function (data) {
             var mainIndex;
-
-            if (!_.every(data, function (item) {
+            if (_.every(data, function (item) {
                     return _.isObject(item);
                 })
             ) {
-                return data;
-            }
-
-            mainIndex = _.findIndex(data, function (item) {
-                return item.isMain;
-            });
-
-            if (mainIndex > -1) {
-                data.unshift(data.splice(mainIndex, 1)[0]);
+                mainIndex = _.findIndex(data, function (item) {
+                    return item.isMain;
+                });
             }
-
-            return data;
+            return mainIndex > 0 ? mainIndex : 0;
         },
 
         /**
@@ -130,7 +122,7 @@ define([
                 fotoramaApi: null,
                 isFullscreen: false,
                 api: null,
-                data: _.clone(pushMainFirst(config.data))
+                data: _.clone(config.data)
             };
             config.options.ratio = config.options.width / config.options.height;
             config.options.height = null;
@@ -270,7 +262,8 @@ define([
                 tpl = template(galleryTpl, {
                     next: $t('Next'),
                     previous: $t('Previous')
-                });
+                }),
+                mainImageIndex;
 
             if (settings.breakpoints) {
                 _.each(_.values(settings.breakpoints), function (breakpoint) {
@@ -297,6 +290,11 @@ define([
             settings.$elementF.fotorama(config);
             settings.fotoramaApi = settings.$elementF.data('fotorama');
             $.extend(true, config, this.startConfig);
+
+            mainImageIndex = getMainImageIndex(config.data);
+            if (mainImageIndex) {
+                this.settings.fotoramaApi.show(mainImageIndex);
+            }
         },
 
         /**
@@ -466,7 +464,6 @@ define([
                      */
                     updateData: function (data) {
                         if (_.isArray(data)) {
-                            pushMainFirst(data);
                             settings.fotoramaApi.load(data);
 
                             $.extend(false, settings, {