Open dialog from worker thread

[Reg <reg theduke at>]

Hi there, pyhton hackers.

I have run into an issue with a multi-threaded application using PyGObject.

I have a worker thread that at one point needs to wait for the user to 
confirm.

I am doing this with this code:

  def showPrompt(self, msg, expectInput=False):
    Gdk.threads_enter()

    dialog = Gtk.MessageDialog(self.app.mainWindow, 0, 
Gtk.MessageType.INFO,
    Gtk.ButtonsType.OK, "Backup prompt")
    dialog.format_secondary_text(msg)
    dialog.run()
    dialog.destroy()

    Gdk.threads_leave()

It works fine when I call this method from the main thread where 
Gtk.main() is run.

When I call it from the worker thread I get weird error messages:

(main.py:17834): Gtk-WARNING **: GtkMessageDialog 0x7fbeb0028020: widget 
tried to gtk_widget_get_width inside  GtkWidget ::get_width 
implementation. Should just invoke 
GTK_WIDGET_GET_CLASS(widget)->get_width directly rather than using 
gtk_widget_get_width

(main.py:17834): Gtk-WARNING **: GtkBox 0x28f6d50: widget tried to 
gtk_widget_get_width inside  GtkWidget     ::get_width implementation. 
Should just invoke GTK_WIDGET_GET_CLASS(widget)->get_width directly 
rather than using gtk_widget_get_width

(main.py:17834): Gtk-WARNING **: GtkBox 0x28f6e30: widget tried to 
gtk_widget_get_width inside  GtkWidget     ::get_width implementation. 
Should just invoke GTK_WIDGET_GET_CLASS(widget)->get_width directly 
rather than using gtk_widget_get_width

(main.py:17834): Gtk-WARNING **: GtkImage 0x2a27dd0: widget tried to 
gtk_widget_get_width inside  GtkWidget     ::get_width implementation. 
Should just invoke GTK_WIDGET_GET_CLASS(widget)->get_width directly 
rather than using gtk_widget_get_width
/usr/lib/python2.7/site-packages/gi/types.py:47: Warning: 
g_hash_table_lookup: assertion `hash_table != NULL' failed
  return info.invoke(*args, **kwargs)

(main.py:17834): Gtk-WARNING **: Error loading theme icon 
'dialog-information' for stock: Icon 'dialog-information' not present in 
theme


Any tipps here?
Note that I am using the global lock with threads_enter/leave.


I'm greatful for any advice,

Christoph Herzog