Hi,
I can't associate at a configurable product, the simple products with drop-down option! 
Example:
I can associate a configurable product with the simple products using a visual swatch attribute. But if a simple product has a drop-down option, the association is not possible: when I save the configurable product, I have "Invalid option value" error and the simple product is not associate at configurable product.
In Magento 1 I haven't this error....
Can you help me?
Fabio
No one has this problem?