What is Smart Sizing?

Smart-sized mode means that the entire remote desktop is always visible in the client window, with no scrollbars being necessary. In effect, for the same size client window, smart-sizing shows you more graphic data, while a non-smart-sized client window has to use scrollbars and shows much less.
This has been around for a long time (as early back as 2008 I was seeing) for enabling Smart Sizing of your TS client (Remote Desktop Client).  I now have this set as default (by modifying my Default.rdp).

Example of Smart Sizing

The two RDP connections below show the difference in when using smart sizing and when not.  Left RDP connection is smart size enabled and the right is not enabled.

How to Enable Smart Sizing

To enable smart sizing, you need to open your RDP connection file in notepad (or your favorite editor) and add the following line:

smart sizing:i:1

So your configuration file will be similar to this, note the addition of ‘smart sizing’ line.

Save the file and then launch your RDP icon and you should now be smart sized.  =)