system.nav.openWindowInstance

I am trying to set up my app so multiple instances of the same display can be opened at one time.
I recall from one of the training videos that this can be done using: system.nav.openWindowInstance as opposed to system.nav.openWindow. I have set up my scripts accordingly but still only get one instace at a time. in addition the system.nav.centerWindow command that follows the openwindow command appears to be ignored as when the window opens it is not centered.
is there something else i am supposed to be doing?
i am running ver. 7.3.0
here is the actual code:
system.nav.openWindowInstance(‘Detail_PS_DC’, {‘Name’ : ‘DC-1 Power Supply Detail’, ‘Pulse’ : 0})
system.nav.centerWindow(‘Detail_PS_DC’)

Thanks,

Sorry, just got it.
Apparently the instances of the display were being opened behind my main window.
I changed the layer and dock index of the window i was trying to open multiple instances of to a number greater than that of the main window and now works.