The sequence of objects and designs can be changed using the Objects view. One way is to right-click on a selected item which will cause a pop-up menu to be displayed. That menu has options to move items earlier or later in the sequence.
You can also drag and drop items in the tree to re-sequence them. Dropping an item (let’s call it ‘B’) on another (called ‘A’) will place that dropped ‘B’ item right after ‘A’ in the sequence. If you drag an object onto the design icon, then that drop will be placed at the head of the design.
You can also re-sequence selected designs and objects using the ‘Sequence Objects’ command on the Edit menu.