3.4 Selection Commands

  The current selection is a subset of the displayed shapes. Shapes in the selection have visible selection handles. The shape in the selection that was first selected has black selection handles and the other shapes in the selection have grey selection handles. The following operations on the selection exist:

• Select a single shape. Click button-1 on an unselected shape (node, edge). The selection will contain only this shape which will show black handles. 
• Add a shape to the selection. Click button-2 on an unselected shape. The first selected shape will show black selection handles, the other selected shapes will show grey selection handles. 
• Remove a shape from the selection. Click button-2 on a selected shape.  The selection handles disappear.
• Empty the selection. Click button-2 somewhere in the background.  All selection handles disappear.
• Select a part of the diagram. Drag button-1 starting in the background. The area that you are selecting, is enclosed by a stippled box, and its bottom-right corner is attached to the mouse. If you release button-1 then every shape that was (partly) inside the stippled box is selected and every other shape outside the box is unselected. One of these selected shapes will show black selection handles, the others will become grey. 
• Make selected shape first selected. You can enforce that a selected shape is the first selected by clicking button-1 on an already selected (grey) shape. The selection handles of the old first selected shape will become grey and the clicked shape will become black.
• The Select All command from the Edit menu  selects all shapes of the diagram. By clicking button-2 in the background you deselect all shapes.