During my exploration of NAV2013 I found out that the NAV development team also changed the "Go To Definition" functionality. In this example I'm using Page 42 "Sales Order".
In NAV2009R2 this context menu is shown when right-clicking the "SalesLines" sub page.
However, when doing the same thing in NAV2013, you get this:
Conclusion: In NAV2013 you can now easily open the used sub page with "Go To Definition" or Ctrl+F12 which will save you a lot of switching back to the object designer!
Note: Do not forget: The next Dutch Dynamics Comunity Event is this evening in Gorinchem (NL) with, among others, a session presented by Partner Ready Software (Gary Winter, Eric Wauters (Waldo) and Mark Brummel).