Minimum characters per post/message should never be '0'

ACP> General> Post Settings> Minimum characters per post/message:

When this option is set to zero in the ACP it is still necessary to have at least one character to post otherwise you get the error:

"Your message contains too few characters."

Either you should be allowed to submit an empty PM or the option to set it to zero should not be available.

Similar to: http://tracker.phpbb.com/browse/PHPBB3-8442?page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel