Rob,
Unfortunately, that's how it is .. transfers only what you see on your screen. Can be expanded slightly by changing what's viewed on your screen (ie. removing some of the view, such as tools, etc.)
However, that said: tx that to "imaging" or to another such program (notepad) and draw your box in a more square pattern, cut and paste it and you'll fill more of the page (horizontal dimension will be 'filled.') May lose some resolution, though ..
Other choice is to print to file, as a *.jpeg and then edit the resulting image ..