Disable HTML tab

Hi Oblax,
To hide Preview & HTML tabs, I use CSS to target those ones by their ID and hide them like this :

#edButtonHTML { visibility:hidden; }
#edButtonPreview { visibility:hidden; }

In my case, I use the Fluency Admin 1.1 theme (2.5+ version required) – great one by the way! – and add those lines above at the bottom of (…)/wp-admin-fluency/resources/fluency.css file.