WP3.9 Visual Editor broken on multisite

Hi,

we run a multisite with 3.9 and since the visual editor is broken.
there is no usable textarea anymore and the button are completely missing.
touching the resize corner results in a sudden disapearence of the “white blank space”.

We have disabled ALL plugins without any change. we also purged the cache, restarted the php-fpm and the webserver itself. no change at all.

wed like to encourage you to roll back your changes at the visual editor so ppl can use it again.

best regards

Simon