Still reproducible on Solaris 10 on SPARC.  You have to left click in the
Class tool on a class or feature name so that there is a blinking cursor.
Then pick the same class or feature name that contains the blinking cursor
and move mouse directly to the right, so that it is on the same line.
Stop moving.  The line connecting the stone to the class or feature is erased
and never reappears unless I move the mouse.  When I do move the mouse, the
line that was supposed to have been drawn appears but there is now a second
line connecting the class to the oval.

Reopening report.