Cancelling Xgrass windows

[Conn Copas]

I'm having problems with the 'cancel' button which is available with most of
the text windows which Xgrass produces. This option clears the contents but
does not close the window. Worse, it subsequently prevents me doing a manual
close from within the mwm menu. My first problem is presumably to discover
whether this is a quirk of our system (HP 9000-750; UX 8.0; X11R4; no Ansi).
Can anyone give some general pointers to what I should be looking for? (I have
minimal X knowledge). I presume that code for the cancel button is nicely
encapsulated somewhere. How do I find it?

-- 
Conn V Copas
Loughborough University of Technology          tel : +44 509 263171  ext 4164
Computer-Human Interaction Research Centre     fax : +44 509 610815      
Leicestershire  LE11 3TU              e-mail - (Janet):C.V.Copas at uk.ac.lut   
G Britain                                      (Internet):C.V.Copas at lut.ac.uk