How exactly do you expect to specify it. Do you say "I always want it to be 20 points" and allow QT to center the chart inside those 20 points, or do you want to say "I want it to be from 40 to 60"?
It may be trivial, but if IB put in a feature in their program that facilitated such redistribution of quotes, they would get a call from the exchanges and would have to remove it or lose their data sources.
The reason why programs like QuoteTracker do not allow you to connect to IB anywhere else except on the same machine is the "redistribution of quotes" thing. Exchanges really frown on this and would move to shut down anyone who would publically disseminate such a program.