It has been reported by several people that OmniGrowl 3.0 is opening its preference window at startup even though that option is not checked. I consider this top priority for a fix, but unfortunately I am on vacation until July 3 and have no access to the source to fix it. It will be fixed by July 7 or earlier. Sorry for the inconvenience.

If there are any other issues besides this one please report them to woodenbrain at kagi dot com so a proper maintenance release can be produced ASAP after my return.