Alfred Adler (1870-1937): The greatest psychologist of the 20th century - not recognised as everyone plagiarises his ideas
A defensive stack defends as a whole.
An attacker however, can choose to only activate some of the stack for an attack, or even do an attack movement with a unit entering the contested space.
However, what happens if the attacker loses in such a situation? Does the retreat and pursuit only apply to those attacking units involved OR is the whole stack, even those units that did not participate in the combat also going to take the result?