There are three separate functions.
Get ( WindowDesktopHeight ) returns for the "desktop space", in other words the maximum available height for a given monitor
Get ( WindowHeight ) returns overall height of the "window on which the script is acting"
Get ( WindowContentHeight ) returns height of the content area within that window
1. the total height of status area, toolbars and bottom of window is Get ( WindowHeight ) – Get ( WindowContentHeight )
2. Get ( WindowDesktopHeight ) is not relevant to the above, except to define the limit
3. You should design for the smallest monitor likely to use the DB (no good designing a layout for a 27" monitor if it is to be deployed on a 13" laptop)
2. It is depend on users setting, not always have fixed width or height.
3. It is an "Example", then not "should return". MDI means "application window", then rarely same as monitor resolution since usually there is windows task bar, window title bar, window menu.
Another example on my win10, monitor is 1280x768, maximized FM app window, the function returns 1280x685. Moving windows task bar bottom to left, get 1218x725.