Change the type of an existing layout panel
By default, a Grid layout panel is used as the top-level layout container (LayoutRoot) within a user control, window, or page document in a Windows Presentation Foundation (WPF) or Microsoft Silverlight application project. In almost all cases, this should be sufficient for top-level page layout.
Right-click the layout panel that you want to change, point to Change Layout Type, and then click the new type for the panel.
In some cases, switching the panel type will cause the child objects of the panel to be rearranged according to the new attributes they inherit. For example, changing the layout type from a container that accepts multiple child objects, such as a grid panel, to a container that accepts only a single child object, such as a ScrollViewer object, will lead to an extra container getting added inside the ScrollViewer object.