In layout mode every part has a discriptive name (header, footer, body, sub summary, etc)
before FMP16 we were able to change the direction of this discription (horizontally, vertically)
With FMP16 the button/icon to change that direction is gone.
I have not found any replacement for that button.
Searched the Status Toolbar, View Menu, Windows Menu, Part Settings, Layout Settings …
[cmd/CTRL] + Clic on the part label to switch orientation