Fix item positioning on grab.

We were invoking grabItem too early. grabItem redraws the element
already absolutely positioned, which messes with offset measuring.
It was causing items to "jump" to the left a few pixels after grabbed.

drag_and_drop_v2/public/js/drag_and_drop.js

@@ -1384,7 +1384,6 @@ function DragAndDropBlock(runtime, element, configuration) {
             var item_id = $item.data('value');
             var item = getItemById(item_id);
             var $document = $(document);
-            grabItem($item, 'mouse');
             publishEvent({
                 event_type: 'edx.drag_and_drop_v2.item.picked_up',
                 item_id: item_id
@@ -1392,7 +1391,6 @@ function DragAndDropBlock(runtime, element, configuration) {
 
             var max_left = $container.innerWidth() - $item.outerWidth();
             var max_top = $container.innerHeight() - $item.outerHeight();
-            var item_size = {width: $item.width(), height: $item.height()};
             // We need to get the item position relative to the $container.
             var item_offset = $item.offset();
             var container_offset = $container.offset();
@@ -1400,8 +1398,9 @@ function DragAndDropBlock(runtime, element, configuration) {
                 left: item_offset.left - container_offset.left,
                 top: item_offset.top - container_offset.top
             };
+
             item.drag_position = original_position;
-            applyState();
+            grabItem($item, 'mouse');
 
             // Animate the item back to its original position in the bank.
             var revertDrag = function() {