Editing product variations not working

Hi,

After updating to CK 1.31, in the backoffice, when clicking on "Edit" at the product variations (inline), they won't expand. When there are multiple variations, clicking on the second variation causes both to expand.

The process indicator runs as usual for a second or two but then nothing happens. It's the same on different machines and browsers.

There are no error reports in the Log. Re-installed CK and the last updated modules, but that didn't fix it.

Any ideas what that could be?

Thanks
paps.