Yes, I also found this problem myself. Some software "intelligently" crop the blank margin of a postscript picture. Always this is just OK. But in some special cases, we set a blank margin of special purpose, for example, to leave some spaces for readers to add some notes. In these cases, the "intelligence" becomes "stupid".
I solve this problem by adding a invisible rectangle (with linewidth equals 0 or with color same as the background color and fillstyle onborder) as large as the screen, i.e.,
Then although there are blank margins but they are not blank in fact. So when the picture is inserted to other software, the margin will not be auto cropped.
set object rectangle from screen 0,0 to screen 1,1 \ lw 0 fillstyle noborder behind