In the Bloody April scenario (#7), find Polk's Corps. In it, you'll find Cheatham's Division. Scroll over it, and you'll see that it contains Stephen's and Johnson's Bde's, and the 1st Miss Cav. Where's the Div HQ? Scroll to the right a bit, and you'll see that it's a seperate unit, independant of the Division.
OK, you think, so I'll just add it to Cheatham's Div, where it belongs. Select 'em both, and CTRL-C, and merge them together. Now put the mouse cursor over Cheatham's Div: The other three units have disappeared! Nothing there but the Div HQ and Cheatham --- yet the individual elements still show up on the far right display.
OK, that's weird. Maybe some kind of display glitch? So you un-form the division into it's individual elements. Oops! Now you have Cheatham, and a single unit called Cheatham's Division that seems to contain all the individual elements (+ the Div HQ)! Only thing you've succeeded in doing is remove Cheatham from command and created some mega-brigade that won't break down to it's individual components!
There's a similar problem with Stewart's Division in Polks Corps as well. Don't seem to have this problem with the other CSA Corps / Divisions in this scenario --- they all combine / breakdown like they should. Something to do with the former problem with the cloned Cheatham / Bushrod Johnson glitch I read about elsewhere?