minor exploit?

[Jabberwock]

2 or 3 star generals get a choice between division/brigade command and corps command. However, if you have two of these generals in the same region, you can form a corps with the lower seniority general, attach the higher seniority general to a division or brigade, and move him into the corps. It becomes his corps, even though he's directly commanding regiments.
This comes in handy when you are short on divisions or generals to command them, but it's clearly not by design.

[jimwinsor]

Yeah I see what you are saying...you get a corps commander who also gets to be part of a division unit as well.

A cute trick that can be seen as a very minor exploit...but a necessary one I think, so as to prevent a greater exploit (lower ranking generals commanding higher ranking ones in the command structure).

[Pocus]

This is a slight abuse that we know about, at first it was allowed, and then the option has been disabled in the interface, because we thought it would be confusing for new players to understand that you can command both a corps and a division at the same time.

I think the AI use the trick

A note of interest about this though: in battle, you get 5% bonus for each point of the stack commander, and 3% for each point of the (embedded) unit commander (division, brigade, whatever). But if the general is the same, you only get the 5% bonus. Conclusion: you still have a big benefit of having 2 leaders if you can.