[Groff] oddity in pic : absolute positioning requires "move" first.

[emmanuel chemla]

Hello to all,

I have a small quizz asking to define a task priority. The user can answer
using one of the four options.
I want those options to have a small ident of 0.8 i.

So here's the code :

\f[BMB]\s11Task priority : \s0\fP
.sp 0.05i
.char \[radiobutton] \f(ZD\N'109'
.PS
"\f[BMR]\s11 \[radiobutton] important and urgent \s0\fP" at (0.8i, 0.25i)
ljust ;
"\f[BMR]\s11 \[radiobutton] important and not urgent\s0\fP" at (3.5i,
0.25i) ljust ;
"\f[BMR]\s11 \[radiobutton] not important and urgent\s0\fP" at (0.8i, 0i)
ljust  ;
"\f[BMR]\s11 \[radiobutton] not important and not urgent\s0\fP" at(3.5i,
0i) ljust ;
.PE

But strangely, it won't  work !
In order to fix it (that is, getting the options indented) I have to insert
a dummy 'move' first, like this :

\f[BMB]\s11Task priority : \s0\fP
.sp 0.05i
.char \[radiobutton] \f(ZD\N'109'
.PS
.\" dummy move :
move 0.0001i;
"\f[BMR]\s11 \[radiobutton] important and urgent \s0\fP" at (0.8i, 0.25i)
ljust ;
"\f[BMR]\s11 \[radiobutton] important and not urgent\s0\fP" at (3.5i,
0.25i) ljust ;
"\f[BMR]\s11 \[radiobutton] not important and urgent\s0\fP" at (0.8i, 0i)
ljust  ;
"\f[BMR]\s11 \[radiobutton] not important and not urgent\s0\fP" at(3.5i,
0i) ljust ;
.PE

With this fix, it does work as intended.
I use cygwin with groff version 1.21.
I'd like to know if it's a normal behaviour, and if indeed, can someone
explain the logic ?

Thanks.

--
Emmanuel