opendialog maximized?

Can anyone tell me if there is a way to use opendialog so that 
the windows that open up are automatically maximized?

In the xul for the dialog I have:
persist="screenX screenY width height"

And in the js file for the dialog I usually have:
window.openDialog('chrome://some.xul',"","chrome,modal,dialog=no,centerscreen,resizable,minimizable" 
..

That works ok but in order to maximize that window, I have to 
set a timeout and watch for the window opening, then maximize 
it.  And it doesn't always work depending how busy the cpu is.

Is there an option to have the dialog be automatically opened 
maximized?  Thanks