Question: What is an "IM Preedit Style"?

[b greiner t-online de (Benjamin Greiner)]

I've stumbled upon the expression "IM Preedit Style" in gtk+ and have no
idea whatsoever what it could mean. As the expression is too English for
a word-by-word translation, I need to know what it means.

Thanks a lot,
Benjamin
-- 
> Wobei ich das Bindestrich Verschwinden auch f�r ein Un Ding halte.
Die Binde Striche werden alle f�r die unn�tigen Apostro'phe ben�tigt.
(Alexander Nald in dafk)