Many menu commands operate on the set of currently selected objects. An individual object is selected by choosing the pointer tool from the tool strip, pointing at the object and clicking the mouse button. A selected object is indicated by it being displayed with inverse highlighting.
Groups of objects can be selected by clicking in open space and with the mouse button held down dragging a dotted rectangle around the group. If more than half the object is included in a rectangle the object is selected.
The selections can be extended to include or exclude objects by using the Shift key in conjunction with the mouse button. It has the effect of toggling the state of the object between selected and unselected.
All the objects in the path between two end objects can be highlighted by clicking on the first node (or link), then, with the Ctrl and Shift keys held down clicking on the second node (or link).