Forms and threads...

I have an application, that starts with a "menu" form.

Each menu item points to a method in differing class libraries... which I
start up in a seperate thread (so that the menu is still active). The
classes will normally display a form. This allows several menu items of
the whole application to run at once (in seperate threads).

This all works well...

but. I want to change the application so that once you select a menu, the
"menu" form hides itself and then only reappears if you click a hot spot on
the status bar on the form...

I can create the hot-spot to click, no problem.. but how do I message back
to the menu form to redisplay itself? It would be a little impractical
for me to go through all my classes and create some sort of event mechanism
at each point - I'm hoping that i can just add something into my base form
(that all my forms inherit from) to do the messaging

Anybody offer any guides?

Thanks
Simon