Selecting and dragging items
Selected items are surrounded by a rounded box with a translucent background. The rounded box will also stretch down to enclose the item's children, but they are not selected unless they have their own boxes around them.
To select an item, click in its gutter.
To select multiple items, hold Command while clicking.
To select multiple consecutive items, drag along the gutter next to the items.
Drag items around by their handles to reposition them in the document and change their levels. While you are dragging, a black arrow shows where the item will land when you let go of it. Dragging a parent item will bring its children with it.