First off, you can have multiple Force Data, Edit Task and View Task dialogs. The first one of these that is opended is termed the "first" dialog. If you select another unit, order or plan task then the data for the current selection will update the date in the first dialog of the appropriate type. So if you open the Edit Task dialog it will display the data for the current selection. Click on another order and it will show the data for the new selected order.
In other words it gives you the same functionality as we used to have with the sidebar.