Strange PM problem for some members no "message" box appears

[boro_boy]

See image below:

The message area where you usually type, isn't coming up for some members. 

But other members it is, these members are in the same usergroup so their settings should be the same as i've never changed any member settings.

Its only just recently happened too, i've have 2 people on the forum stating this. I'm running 4.7.0 Beta 9.

Many thanks 👍

[Marc]

Please could you ask those users to clear their browser cache first of all? I believe it may be a cache issue they are having. If that does not correct the problem, please could you find out what browser and operating systems are being used?