I'm testing my app in Natty 2nd beta, in which most applications are showing the new overlay scroolbars, I guess only non-native GTK apps can't show it (like LibreOffice or Firefox).
My app is coded using Python and pygtk so I thought the overlay scrollbars should be enabled by default but I was wrong. I tried to set the environment variable LIBOVERLAY_SCROLLBAR to 1 in both terminal (previously to the app command) and inside the python code via os.putenv(), but it's still showing the old-fashioned scrollbars.
What am I doing wrong?