Selects all objects in the scene.
Deselects all objects or elements. If the Points tool is active when you invoke Deselect All, all the points of the selected object will be deselected. Similarly, if the Polygon tool or Edge tool is active, all polygons or edges of the selected object will be deselected.
Adds the children of the selected object(s) to the selection. This is especially useful when you want to record keyframes for the selected objects and their children.