The QSO Window displays all information for a single QSO. This is the window you will use for logging or to modify an existing QSO. 

The QSO Window showing all available fields. The window can be resized in different sizes showing fewer fields as illustrated below.

The same contact is shown, but now the QSO Window is smaller.

The Same Call Window follows the QSO window, showing all contacts with the station. This window can also be used to confirm QSOs using the F2 key.

The Same Call Window showing all contacts with the same station, including QSL and confirmation information.