diff --git a/tryton/common/common.py b/tryton/common/common.py
index 4b9dd43e1c..672bf3d7f8 100644
--- a/tryton/common/common.py
+++ b/tryton/common/common.py
@@ -842,7 +842,10 @@ class RPCProgress(object):
                     progressbar = gtk.ProgressBar()
                     progressbar.set_orientation(gtk.PROGRESS_LEFT_TO_RIGHT)
                     vbox.pack_start(progressbar, expand=True, fill=False)
-                    win.add(vbox)
+                    viewport = gtk.Viewport()
+                    viewport.set_shadow_type(gtk.SHADOW_ETCHED_IN)
+                    viewport.add(vbox)
+                    win.add(viewport)
                     win.set_transient_for(self.parent)
                     win.set_modal(True)
                     win.show_all()