on the Watch Data view and select Expand Trees from the drop-down menu to expand a selected node. To expand all the nodes, click the Expand All Trees toolbar icon 
on the Watch Data view.If you want to view the contents of a mapped item in the Watch Data view, you must expand the node for that item.
To quickly expand a tree in the Watch Data view for a mapped item, right-click the node for that item in the Name column and select Expand Trees.
The Watch Data view expands the selected node and displays the subnodes, fields, or variables under the expanded node.
Note: Alternatively, you can click the View toolbar icon on the Watch Data view and select Expand Trees from the drop-down menu to expand a selected node. To expand all the nodes, click the Expand All Trees toolbar icon on the Watch Data view.