Major Description
on the trunk, defType currently defaults to the "lucenePlusSort" option, which has legacy support for syntax like "field:value;sort_field desc" where the semi-colon character is considered special if-and-only-if there is no "sort" param.
this syntax has proved confusing to new users on at least one occasion, and has been deprecated for a while.
In 1.4 we should change the default to use defType=lucene and add a note for people upgrading about how to force the legacy semicolon behavior.