GTK signal handlers need to return True/False

Since we deal with minimize/expose/show/hide routines ourselves, we
don't want these signals passed any further.

NOTE: if no return type is specified, it is automatically None which
usually is translated to False. That might trigger some weird behaviour,
up to and including rare and hard to reproduce GTK crashes.

pyfpdb/fpdb.py

@@ -656,6 +656,8 @@ This program is licensed under the AGPL3, see docs"""+os.sep+"agpl-3.0.txt")
             else:
                 self.window.set_skip_taskbar_hint(False)
                 self.window.set_skip_pager_hint(False)
+        # Tell GTK not to propagate this signal any further
+        return True
         
     def statusicon_menu(self, widget, button, time, data = None):
         # we don't need to pass data here, since we do keep track of most all