Do you lose your class supernatural abilities when using shapechange?

One of my players is wondering whether you lose the supernatural abilities derived from your class when changing for using shapechange. To me the answer seemed pretty straightforward since the spell says

You gain all extraordinary and supernatural abilities (both attacks and qualities) of the assumed form, but you lose your own supernatural abilities.

But then he found this link

https://forums.giantitp.com/showthread.php?517934-The-3-5-Shapechange-Handbook

And at page 6 it says

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But i couldn’t find any source for this claim. I would like to know which version is right and where i can find an official source that clarifies this (unless it’s simply what the spell says and you lose all supernatural abilities)