diff --git a/tryton/common/common.py b/tryton/common/common.py
index 815f2ee685..0f4dd0c5d4 100644
--- a/tryton/common/common.py
+++ b/tryton/common/common.py
@@ -255,7 +255,8 @@ def request_server(server_widget):
 
 def get_toplevel_window():
     windows = [x for x in gtk.window_list_toplevels()
-        if x.window and x.props.visible]
+        if x.window and x.props.visible
+        and x.get_window_type() == gtk.WINDOW_TOPLEVEL]
     trans2windows = dict((x.get_transient_for(), x) for x in windows)
     for window in set(windows) - set(trans2windows.iterkeys()):
         return window