From FreeCAD Documentation
- Select one or more objects.
- Invisible objects can be selected in the Tree view.
- Be careful when you use Ctrl+A to select all objects in the Tree view. This will also selects sub-elements of PartDesign bodies and objects used for Part Booleans. In most cases these should stay invisible.
- Objects used for Part Booleans are also selected when you use Ctrl+A in a 3D view.
- There are several ways to invoke the command:
- Select the View → Toggle visibility option from the menu.
- Select the View → Visibility → Toggle visibility option from the menu.
- Select the Toggle visibility option from the Tree view context menu. This option is not available in the PartDesign Workbench.
- Select the Toggle visibility option from the 3D view context menu.
- Use the keyboard shortcut: Space.