tbl and nroff -mm

[Chuck Forsberg WA7KGX]

With PC-AT Xenix 1.0, when I use the command
	tbl -TX ymodem.tmi|nroff -mm|col|head -23 >/dev/color&
on the following:

.FG "Header Information used by YMODEM Implementations"
.TS
allbox;
c c c c c c c
l l l l l l l.
Program 	Name	Length	Date	Mode	S/N	1k Blocks
Unix rb/sb	yes	yes	yes	yes	no	yes
VMS rb/sb	yes	yes	no	no	no	yes
Pro-YAM 	yes	yes	yes	no	yes	yes
cp/M YAM	yes	no	no	no	no	yes
MODEM76 	yes	no	no	no	no	no
.TE

I get the expected table within a grid.  However, when I include this
within a larger mm document with the sequence:
	mm -t -c -rB1 -rO0 -rW74 yproto.mm >ymodem.doc

	.DF CB
	.so ymodem.tmi
	.DE

The same file isn't set up as a table (allbox, etc. appear in the output).
Am I doing something wrong or is this Xenix bug number 62?
-- 
Chuck Forsberg WA7KGX	..!tektronix!reed!omen!caf
Omen Technology Inc 17505-V NW Sauvie IS RD Portland OR 97231
Voice: 503-621-3406	Modem: 503-621-3746 (Hit CR's for speed detect)