Nexus 7; input keyboard

[dharmer]

On my Nexus 7 (2013) I have selected Swiftkey as my default keyboard. However, in Aquamail the original Nexus input keyboard shows. How do I change this to my new default keyboard, i.e. Swiftkey? I cannot find a setup for this. Help! I am sure there is a simple answer but I do not know it! Aquamail appears not to use my default Nexus 7 keyboard selection.

[Kostya Vasilyev]

Please see the screenshot (taken on a Nexus 7, but I could have used any of my other dozen or so devices).

Do you know how to switch the current keyboard? It's in the status bar when entering text.