The example extcab3.hoc does not work because the membrane mechanism
called extracellular does not know about xcaxial (axial extracellular
capacitance) at this time.

break, continue, return statements should not appear inside
a statement of the form 
	<section> {....}
since the section stack will not be popped.  At this time such
statements have to complete normally.

If you quit the graphics X window, the next plot command will cause
NEURON to exit without saving edit buffers.