Store Community Support Documentation

There is an extra "SEND" button in messenger.

How does one go about removing it?  It doesn't work properly and it causes my members quite a bit of grief.  I mean - I like dudindancy as much as the next guy, but that extra button is kinda broke.  Doesn't clear the typing field when it submits the text.  Anyway - a little help finding the switch to turn it off?  Anyone?  :-)