Sounds like that's specific to the Mac LibraryThing app.

Dragly and I have been working on the Qt version of mbarcode, apologies it's taking a while but I'm pretty busy at work and he's got coursework to do.

I hope to soon (i.e. within a week, he says ) have a basic version out (with only very basic plugins) so that people can start adding their own more complex (and useful) plugins.