At this moment there is no direct way (e.g. a ProcScript function) to get the size of the application shell window. The function $windowproperties only works for form component windows and $applproperties does not have this functionality (yet). Looks like a valid wish.

There is, however, a way to get the desired info by using the C Call-Out API. The Uniface 3GL function ugethwnd (that is part of yrtl.dll) will give you the window handle of the application shell window. And if you use that handle to call the Win32 API  function GetWindowRect then this will give you the top and left x-coordinates and the top and bottom y-coordinates of the window. With some simple math you then can calculate the width and height of the application shell window.

I hope this helps.