Thread and tkMessageBox (Synchonimous)

[Askari]

I think that my problem is in the syncho between main thread and my
thread created with (with thread.start_new_thread(...) ). But, I don't
understand the method for syncho with a thread...

I want pop a message to user with
tkMessageBox.showinfo("Title","Message") but when this command is in
my thread, it's don't work (and my main thread give no reponse
(crash)).

How I can pop a message (or question) with a thread?

Askari