The best solution I have found is to implement a fake tab framework, so MOC i socnfigured to have a single tab application, but you implement the same tab look inside your application.
Using html frames you can then host seperate applications inside each tab in exactly the same way but you can keep things that require global scope in the main application.
This also gives you a lot of control of the look and feel - allows you to change the size / colors etc of the tabs - change the navigation completely for example vertical tabs instead of horizontal.