the "month chooser" at the https://www.scirra.com/store/seller-sales seems broken, the options are there (you can see it in Firebug) but it isnt clickable anymore. Not in Firefox and not in Chrome :/
Having the same issues as well. Am sure Tom is working on it now.
Develop games in your browser. Powerful, performant & highly capable.
Tomorrow Think it's just a CSS problem.
Fixed! Sorry about that!