Can't delete existing core formations in campaign game

[interstaterunner]

Haven't played this game in quite a while. I used to be able to change individual units and even delete existing core formations with the 'Expand Core' button in the Unit Repair Menu. Also when changing a unit it used to be a snap to highlight/click on a diff unit and change that one too. Can't seem to do that either =/ Is this a bug with playing it on Vista or did I make a mistake when installing it in it's natural folder? Or is this a deliberate change? Just wondering =)