Thank you Dragan and Tamar for reply.

yes i suppose the vfp main window alias _screen is also a console output and dont have native scrollbars(0,1,2)
the form even if it's scrollable ,have also the same limitation for outputing ? and ?? or form.print commands:
they are troncated and written in visible window only.
but in the form case,commands ? and ?? can be outputed to the form (showWinowd=0,1,2) background only if the
form.scrollbars=0 (readonly property at runtime).this is another problem raised !
it dont work at all for scrollbars set to 1 or 2!

i suppose the command ? and ?? use an old gdi API to draw the char strings on visible area only using physical
coordinates ( as TextOut API ?).

I am surprised scrollbars are "invented" since vfp6 ! windows APIs do that more early with
createWindow/CreateWindowEx APIs!
this is maybe for the hwnd property dont exists originally in vfp (or exits as other definitions diffrent of window.s)

Of course alternative of this problem is to re direct the outputs to external scrollable txt file as this code :

set cons off
local m.afile
m.afile=addbs(sys(2023))+"myfile.txt"  &&temp txt file 
SET ALTERNATE TO (m.afile)
set alternate on
? "****************************************************"
? "*        I                COS(I)            SIN(I) "
? "*****************************************************"
for i=1 to 1000
? i
?? cos(i)
??sin(i)
endfor
set alternate off
set alternate to
set cons on
modi comm (m.afile)
erase (m.afile)