One of the benefits of having the Toolbox Calendar organised vertically is to be able to select weeks across the top easily and therefore long periods of time easily.
In order to change the view to horizontal tick the icon in the bottom right marked 'horizontal'. In horizontal mode, the weeks number is located along the left hand side, and the days of the week are along the top. This setting will remain active until unticked, so no need to keep ticking the box between logins.
The Toolbox Calendar can now be switched between vertical and horizontal view, depending on your personal preference. In order to use this feature, you will need to have version 6.8 installed.