The elements Content Wizards, Sections, Selection Groups, and Text Blocks can contain mandatory and optional items. Mandatory items are items that will be automatically selected in the result of the Content Wizard. All items added directly to the Content Wizard element or a Section are mandatory. They will be shown as read-only in the Content Wizard dialog in which items can be selected.
If items are added to a Selection they are optional. You can select optional items in a selection dialog generated by the Content Wizard. To differentiate optional items, which are set to default selected or are mandatory, they are marked bold in the tree view.