I am encountering a problem using AutoCAD Civil 3d 2012. When finishing a certain command and going back to the ribbon, my cursor does not want to go out of the modelspace. So i can't click any command in the ribbon, or in any other program outside of AutoCAD.
Even when pressing escape to stop a command, nothing changes. Using the viewcube solves this problem for one time. But every time I draw a line or even zooming, the problem comes back again. This is very annoying.
It is hard to give suggestions without more information. - Is it always the same "certain" command - and which is it? - Is the cursor still visible or disappearing? - Can we exclude hardware problems, especially graphics card issues? See http://usa.autodesk.com/adsk/servlet/syscert?id=18844534&siteID=123112 - A early solution for a similar issue was do turn off snapping - it's worth a try.