> For the second time this week, I found a need to repeat an IDL command for it to take full effect.    Below is the sample program on my Mac

> pro testwin

> print,getprimaryscreensize()

> window,xsize=870,ysize=870,retain=2

> print,!D.y_size,!D.y_vsize

> print,!D.y_size,!D.y_vsize

> return

> end

> The output is

> IDL> testwin    

>         1440         878

>          870         870

>          856         856

> So when I first ask to print !D.y_vsize it returns 870, but when I immediately ask again it returns 856.

> This problem is avoided if I put any sort of wait statement after opening the window.    It appears to take a finite time, after I ask IDL to open a window with a Ysize of 870 pixels, to realize that the toolbar is using up 22 pixels and adjust !Y.V_SIZE accordingly.

> This delay is what may have caused the difficulty in getting the Mac useful screen size

> ( http://www.idlcoyote.com/code_tips/goldilocks.html ).    My solution for getting the useful Mac screen size would now be the following:

> function getmacsize

> xy = get_screen_size()

> window,xsize=xy[0],ysize=xy[1],/free

> wait,0.01

> out = [!D.x_vsize,!D.Y_vsize]

> wdelete,!D.window

> return,out

> end

> Of course, this will give flashing but at least it will give the right answer.

> Cheers, -Wayne