I just notice this. When I open RC1, I was able to login with no issue. When I open RC2 and I tried to login, I encountered 

Invalid Request! No Data was saved

When I checked RC1, it is now logout with session expired or invalid. Both RC are hosted on a different physical server.

It seems it is cookie related. Do you think it is on my apache config? 

On Thu, Mar 22, 2012 at 7:09 PM, Claudio Kuenzler <ck@claudiokuenzler.com> wrote:
Are the two webmails on the same server?

I've just made some tests:

Firefox 11, same window, two tabs, two different roundcube webmails each hosted on a different physical server -> works fine