Faq/Writer/163

How do I select an object in the background
Use the key combination.

Going further

You can also use the tool Select in the Drawing toolbar (first tool on the left of this toolbar) to surround the object to select:
 * click and keep the mouse button pressed;
 * move the mouse to surround the object (the selection is displayed by a dashed line around); and
 * release the mouse button: the object is selected.

The Navigator (Sidebar or menu or ) also allows you to select most of the objects.