In the Objects window, click an object name or ID in the tree to select that object in the drawing. This is particularly useful with large assembly units since you can use the object name or ID to uniquely select the correct object. Holding down the CTRL key allows you to click and select several objects one after the other. If you want to select several objects which are positioned one on top of the other, you must first select the top or bottom object. While holding down the SHIFT key, you can then select all objects between the object already selected and the object that you click. If an object is already selected, clicking it will cancel the selection.