Note to the site author: Using Chrome's translate tool seems to break your UI. Upon first visit, I was prompted to translate from Portuguese to English and accepted. Subsequent visits required I click the "Translate this page" button on the right side of the URL bar. (Edit: Chrome 1490.7827.201 on Windows 10).

When translated, clicking the Solver drop-down (default 3x3x3) displays:

Unexpected error

Something went wrong. The current screen broke unexpectedly. Please try again or switch routes to reload it.

Interesting, but the site has support for 9 languages, what language were you using?