thread's access to widgets: freezes all widgets

["F. Kater" <f kater2 gmx net>]

Hi,

I am sure I have forgotten some essetial detail that someone probably
knows:

* I have a thread running.

* As long as it just does not try to display something (using
  gtk_label_set_text()) it works and finishes ok and I can keep on
  pressing buttons etc.

* If the thread trys to communicate with any widget then nothing is
  actually displayd as it should, and, all other widgets don't react
  anymore.

What's wrong?

Felix