I noticed the same bug using the commandline interface, tags are not displayed correctly.
$ aptitude show autoconf Package: autoconf [...] Tag: code-generator, devel::{buildtools, interface::commandline, lang:c}, role::program, scope::utility $ The problem seems to be caused by incorrect parsing of grouped tags; autoconf, for example, has the following tags in the Package file: Tag: devel::{buildtools,code-generator,lang:c}, interface::commandline, role::program, scope::utility The tags belonging to the devel:: facet are grouped together using curly braces, and it's very likely that this is what makes aptitude screw up. -- KiyuKo <eof AT kiyuko DOT org> Resistance is futile, you will be garbage collected.
pgp4krA1ERrhT.pgp
Description: PGP signature