> M-: (modify-frame-parameters nil '( (fullscreen . fullheight) (width . 170) ))
 >
 > The height is set, but the width is not.  The documentation seems to
 > suggest that both are frame-parameters and hence can be set together.
 > It works fine if two modify-frame-parameters commands are issued.

Allan, could you please try the attached patch?  It's not very elegant
but maybe it does what is needed.

Thanks, martin.