Installed Roundcube plugin using:
Using RoundCube Webmail With ISPConfig 3 On Debian Wheezy (Apache2)
Roundcube is returning the following error with 15 filters created:
Additional filters can be created within ISPConfig. The max filter limit problem occurs only when attempting to enter more than 15 filters within Roundcube.
ISPConfig is set for an unlimited number of email filters.
'Max. number of email filters -1'
Tested raising the max email filters in ISPConfig to 1000, but the Roundcube still reports max number of email filters reached.