Hi Zuffy! 
I also have a XPS 15. I went to an apple store earlier today, hooked the cinema display to it, and everything worked perfectly.
The problem with the applecontrolpanel is that it won't work if you launch it from within an administrator account. Yeah I know...pretty weird!!
You just need to create a standard user account, and launch the application from there. Worked perfectly for me.
Best regards
I also have a XPS 15. I went to an apple store earlier today, hooked the cinema display to it, and everything worked perfectly.
The problem with the applecontrolpanel is that it won't work if you launch it from within an administrator account. Yeah I know...pretty weird!!
You just need to create a standard user account, and launch the application from there. Worked perfectly for me.
Best regards