ePub, CSS : Bug with 'position: relative' property ?

Hello there,

From the few experiments i've made, 'position: relative' property seems to make elements invisible.
I've only played on this with 'div' and 'span' elements.

The ePub displays fine on Adobe Digital Editions.

That's pretty embarrassing because the IDPF specs seems to allow it.

Does anyone got the same bug or am I wrong somewhere else ?

Thanks