What you mean to say is that when the vertical size is changed, it is ignored unless the horizontal size is also changed.
Agreed
create bitmap 1, 200, 200
ink rgb(0, 0, 255), 0
box 10, 10, 190, 190
ink rgb(255, 255, 255), 0
center text 92, 100, "Hello World"
set current bitmap 0
cls
copy bitmap 1, 0, 0, 200, 200, 0, 0, 0, screen width(), screen height()
text 0, 0, "Fill the screen"
wait key
cls
copy bitmap 1, 0, 0, 200, 200, 0, 0, 0, screen width(), 200
text 0, 0, "Expand horizontally"
wait key
cls
copy bitmap 1, 0, 0, 200, 200, 0, 0, 0, 200, screen height()
text 0, 0, "Expand vertically"
wait key