Opening a view can be done in a number of ways:
double-click an element in the Navigation Area
or select an element in the Navigation Area | File | Show | Select the desired way to view the element
or select an element in the Navigation Area | Ctrl + O ( + B on Mac)
Opening a view while another view is already open, will show the new view in front of the other view. The view that was already open can be brought to front by clicking its tab.
Note! If you right-click an open tab of any element, click Show, and then choose a different view of the same element, this new view is automatically opened in a split-view, allowing you to see both views.
See Move elements, drag and drop for instructions on how to open a view using drag and drop.