I am new to Draftsight and have an Autocad background.

In my sheet (paperspace) set up with a viewport, I zoom into the drawing I want to display at a particular scale. That drawing is inside a rectangle I have created so that when I zoom to the corners, it displays at the correct scale on my sheet. However, I cannot get the drawing to display in the right scale. It seems to always fill the viewport only to half it's size.  

Is there a setting somewhere that I accidentally set?