disable canvasdesigner css link on the preview mode (with canvasdesigner enable)

src/Umbraco.Web.UI.Client/src/canvasdesigner/canvasdesigner.front.js

@@ -206,6 +206,8 @@ var outlineSelectedHide = function () {
 
 var initCanvasdesignerPanel = function () {
 
+    $('link[data-title="canvasdesignerCss"]').attr('disabled', 'disabled');
+
     // First load the canvasdesigner config from file
     if (!canvasdesignerConfig) {
         console.info("canvasdesigner config not found");

src/Umbraco.Web/UmbracoHelper.cs

@@ -1333,7 +1333,7 @@ namespace Umbraco.Web
                                  @"<script type=""text/javascript"">var pageId = '{2}'</script>" +
                                  @"<script src=""/umbraco/js/canvasdesigner.front.js"" type=""text/javascript""></script>";
 
-            string noPreviewLinks = @"<link href=""{0}"" type=""text/css"" rel=""stylesheet"" />";
+            string noPreviewLinks = @"<link href=""{0}"" type=""text/css"" rel=""stylesheet"" data-title=""canvasdesignerCss"" />";
 
             // Get page value
             int pageId = UmbracoContext.PublishedContentRequest.UmbracoPage.PageID;