Can't bring up the contextual menu

Hi all,

I just installed GNUstep last week from sources under Fedora Core
5/x86. I also installed some applications, like GNUMail.

When I set up GNUMail, I faced a little problem when I had to set up my
Sent and Draft folders. The application said : "To set up the sent mail
folder, bring up the contextual menu on the mailbox list for the folder
you want to use...", so as  if I was under GNOME/KDE/Windows, I used
the right mouse button but it didn't work as expected (it brings up the
GNUMail application menu). I said to myself : "It's OK, I'm under
GNUstep, it must be another key combination", so I tried <LeftShift> +
<LeftMouseButton>, <LeftShift> + <RightMouseButton>, <LeftCtrl> +
<LeftMouseButton>, <LeftCtrl> + <RightMouseButton> and all other
possible <ModifierKey> + <MouseButton> combinations, in vain.

What can I do to make it work ?

Thank you for your answers.

Alexandre