Merge remote-tracking branch 'chaika/MC-17948' into Chaika-2019-09-12-CE

Author: veloraven

app/code/Magento/Newsletter/view/adminhtml/templates/preview/iframeswitcher.phtml

@@ -17,6 +17,7 @@
     <iframe
             name="preview_iframe"
             id="preview_iframe"
+            class="preview_iframe"
             frameborder="0"
             title="<?= $block->escapeHtmlAttr(__('Preview')) ?>"
             width="100%"

app/design/adminhtml/Magento/backend/web/css/styles-old.less

@@ -4060,6 +4060,16 @@
     }
 }
 
+.newsletter-template-preview {
+    height: 100%;
+    .cms-revision-preview {
+        height: 100%;
+        .preview_iframe {
+            height: calc(~'100% - 50px');
+        }
+    }
+}
+
 .admin__scope-old {
     .buttons-set {
         margin: 0 0 15px;