Comment 3 for bug 764739

Modified again. Who did add threads_enter/leave around show_error? And why?!
Removed threads_enter/leave on rev. 264
                gtk.gdk.threads_enter()
                try:
                        self.show_error(text)
                finally:
                        gtk.gdk.threads_leave()

Here threads_enter/leave hangs GUI every time an error is showed while works correctly without.