the menu bar disappeared in ubuntu-desktop

[Rhys]

ubuntu maverick netbook edition

When I logged in netbook session, the menu bar of wxmaxima (an algebra
computing software) appears at the top of screen. As same as many
other applications, menu bar dwells on the top.
see http://imagebin.ca/view/jVGB5j.html

When I logged into desktop session, the menu bar of wxmaxima disappeared.
see http://imagebin.ca/view/YiIIMtA.html

I have tried to remove anything relative to wxmaxima by "find ./
-iname "*maxima*" -print " and re-install wxmaxima from repositories.
It didn't work.

Anything that I can do to recover the menu of wxmaxima in the
ubuntu-desktop session? And another program named flashget have the
same problem, which I think it would be better to be mentioned here.

Regards,
xiang