add playlist drag and drop help

dashboard-ui/scripts/playlistedit.js

@@ -171,9 +171,31 @@
 
     }
 
+    function showDragAndDropHelp() {
+
+        if ($.browser.mobile) {
+            // Not implemented for mobile yet
+            return;
+        }
+
+        var expectedValue = "7";
+        if (appStorage.getItem("playlistitemdragdrophelp") == expectedValue) {
+            return;
+        }
+
+        appStorage.setItem("playlistitemdragdrophelp", expectedValue);
+
+        Dashboard.alert({
+            message: Globalize.translate('TryDragAndDropMessage'),
+            title: Globalize.translate('HeaderTryDragAndDrop')
+        });
+    }
+
     window.PlaylistViewer = {
         render: function (page, item) {
+
             reloadItems(page, item);
+            showDragAndDropHelp();
         }
     };
 

dashboard-ui/strings/javascript/en-US.json

@@ -907,5 +907,7 @@
     "TryMultiSelectMessage": "To edit multiple media items, just click and hold any poster and select the items you want to manage. Try it!",
     "NumLocationsValue": "{0} folders",
     "ButtonAddMediaLibrary": "Add Media Library",
-    "ButtonManageFolders": "Manage folders"
+    "ButtonManageFolders": "Manage folders",
+    "HeaderTryDragAndDrop": "Try Drag and Drop",
+    "TryDragAndDropMessage": "To re-arrange playlist items, just drag and drop. Try it!"
 }

dashboard-ui/strings/javascript/javascript.json

@@ -917,5 +917,7 @@
     "TryMultiSelectMessage": "To edit multiple media items, just click and hold any poster and select the items you want to manage. Try it!",
     "NumLocationsValue": "{0} folders",
     "ButtonAddMediaLibrary": "Add Media Library",
-    "ButtonManageFolders": "Manage folders"
+    "ButtonManageFolders": "Manage folders",
+    "HeaderTryDragAndDrop": "Try Drag and Drop",
+    "TryDragAndDropMessage": "To re-arrange playlist items, just drag and drop. Try it!"
 }