This section present how to select/ un-select objects in the scene from the GUI.
You can click on nodes to select/ unselect them.
CTRL + Selection is adding the new selection to the exisitng one.
If several node on top of each other: ALT + CLICK loop over the node bellow the click.
SHIFT + DnD is displaying a black rectangle. When released, all node's whose coordinate projection to the rectangle are selected.