Cannot use overlay-scrollbar anymore on precise

[Giovanni Mellini]

Last updates broke the overlay-scrollbar functionality.
As you can see on the video I uploaded, when I move my mouse near the border of the nautilus window (or any other window) the overlay scrollbar appears but when my mouse goes over the scrollbar suddenly disappear.
This means that I cannot use the overlay scrollbars to move up/down or left/right. This is a big regression, how I can help debugging?

giovanni@trumpet-fish:~$ dpkg-query -l 'overlay*'
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Nome Versione Descrizione
+++-==============================-==============================-============================================================================
ii overlay-scrollbar 0.2.15-0ubuntu1 Scrollbar overlayed widget
giovanni@trumpet-fish:~$

[Giovanni Mellini (merlos)]

I found that this bug is already reported, so is a duplicate. Sorry