Using Visual Studio 2013, you can now drag and drop the XAML controls directly into the document outline. Earlier the control drag and drop was restricted only to the XAML Editor. One of the basic problem due to that restriction was to find and place control in a proper location, mostly when there a big chunk of code.
With the new feature, you can now easily place the control in an exact position by just viewing the outline of the overall document. So, just select the control from toolbox; drag and drop it into the document outline. Visual Studio will automatically update the XAML editor.
While placing the control, you will also get a tooltip message that says which control is getting placed where. For an example; in the below image you can we are placing an Image control inside a StackPanel (Left ) and Placing a GridView control inside a StackPanel ( Right)