I've been considering switching to RC for our webmail... do you know if the RC managesieve plugin and the TBird sieve extension co-exist peacefully?
Partly: RoundCube tries parsing the Sieve-Rules in a certain scheme, if parsing fails (e.g. by editing in ThunderBird and not following the scheme) no rules will be displayed in RC.
Except that, RC + ManageSieve work great.
