The node-type elements are the
variable and the
compartment, as well as the elements used in population submodels. The following procedure is used to add node-type elements.
Note that the button you selected on the tool bar remains depressed until you select another button (i.e. to add a different element, or to change into a different mode, such as label or move). This allows you to add quickly several elements of the same type.
Note that it is not possible to add a node-type element to an area of your diagram that is already occupied. No error message appears, so if this happens, simply click somewhere else where there is sufficient space, or
move existing elements around to make sufficient space.