Since it seems that the Navigation Strip was turned on for everybody today or yesterday, here is a reminder:
You can disable it by going to the
Viewing Options page and unchecking the two boxes below 'Navigation strip display options'.
If you want to disable it in your community don't forget to select said community in the drop-down menu "Work as User" which at the top of the page then to click on Switch.
If you want to prevent it from being displayed in journals which have it enabled for everybody, follow the instructions given in
this guide.