I am having the exact same issue with PowerPoint being giant on my external monitor. I can't understand why all the other Office programs would scale normally from monitor to monitor except this one.
As for why PPT only, I suspect that is because all of the Office programs started as totally independent developments in the 1980's and 90's. It wasn't until the early 1990's that the "Office Bundle" concept was introduced by marketing that they were all
sold in the "same box". That means they were written in different ways. That underlying difference continued even when they changed from DOS to Windows and from Windows 3 to Windows NT and even from the menu to the ribbon. In the Office 2007 development
blog I even saw comments by one manager who said the teams were allowed to effectively do their own thing for placement of buttons and command names so that the ribbons on the various applications were not the same.
So, I suspect that somewhere in the very ancient roots of PowerPoint there is something unique that messes up the scaling. Finding, and fixing it would probably be a huge effort. Since so relatively few people are complaining about it, the fix is unlikely
to happen ... unless it is coincidental with some other change.
If you are curious about the ribbon development here is the blog:
Jensen Harris 2007 Blog - Ribbon UI rationalizations
Microsoft’s traditional Windows and Office interfaces have grown more complex and inscrutable over time. (Microsoft always claims it conducts extensive user interface research, but still revamps the UI every chance it gets. It must be using a different
species of alien each time.) In a touch-oriented environment, rows and rows of small, undecipherable icons just don’t work. Someone at Microsoft seems to have realized that, and perhaps Office for ARM will be truly usable. That alone could move many users
away from the “heavy” x86 version of Office and, thus, Windows.
**Jensen Harris: An Office User Interface Blog** - A LOT of reading, it provides insights into the design of the Ribbon and the underlying (il)logic of the design.
http://abc.salem.consulting.home.comcast.net/~abc.salem.consulting/services.html - A PDF collection of the blogs, easier to read than the
original blogs (257 pg). There is a button on the bottom of the page to download the PDF.
http://blogs.msdn.com/b/jensenh/archive/2008/03/12/table-of-contents.aspx This is an organized Table Of Contents to a large collection of links
to MS Dev Team Blogs about the design and building of the 2007 ribbon.
Why the Ribbon
Why the ribbon, in Word 2003 and earlier MS Stats show:
- only 13% of commands/ features are actively used
- of new feature requests, only 6% did NOT already exist