Interesting issue.
I can confirm it happens on Chrome, Chromium and Firefox.
This must be a javascript issue. Each time you select "latest", something somehow changes the value of the select to null
, which cause the empty box. This does not happen on other installs of Flarum (Here on discuss selecting Lastest sets the select value to lastest
)
From the javascript bootstraping code in the footer of your website, it appears you are running a pre-beta6 version of Flarum. You should probably make sure your forum is up to date before anything else ?