AutoCAD 2012 External Reference Enhancements
AutoCAD 2012 improves the flexibility to spotlight and choose externally referenced files. If you pass the cursor over the sting of an image attaching, DWFTM, or PDF file, a variety preview frame is displayed, even when frames are turned off.
Similarly, passing the cursor over geometry within an attached DWF, PDF, DGN, or DWG file displays a variety preview frame. you’ll select the frame for @ny of the attached refere_nce files to show a frame boundary, with the power to grip-edit a clipped boundary ftame.
Interaction with the External References manager is enhanced to automatically show the frame after you choose a reference file from the l1st.
To support the frame choice behavior, a brand new FRAME SELECTION system variable is included in AutoCAD 2012. (article source: http://heidihewett.blogs.com/)