OK, I'D LIKE TO CHANGE THIS TO A RANT AND RAVE. Sorry to yell, but I've just spent the better part of two hours on the phone with PTC tech support about this issue. It seems that the behavior is different between a regular part and a sheetmetal part. IE, when you right mouse click a feature in the model tree and then pick EDIT, you can then right click the dimension on the screen to get to the properties window to change the nuber of decimal places. However, since I had a sheetmetal part you cannot right click the dimension on the screen to get to the properties window, you have to go through the menu manager to select dimension and that gets you to the properties window.
This is piss poor (excuse me for my language) software design to have the exact same function work differently between the two types of modules.