Landscape keyboard not visible [Solved]

Had a problem with Swiftkey, where portrait keyboard showed correctly, but landscape keyboard was not clearly visible.

Looked everywhere on forums and frequently asked questions, but failed to find an answer.

Eventually found that clearing cache AND data resolved the problem, with the landscape keyboard showing up correctly.

Probably caused by recently updating to Android 9.0 (Pie), as on 8.0 it worked correctly.

Hope this is of use to someone with a similar problem.