How can I persuade my MX715 that I mean what I say: paper normally to come from the rear tray.

[ggoss]

Yesterday, my printer decided that it would rather be fed from the cassette.  I had changed nothing and since then have re-iterated umpteen times that I want it to take paper from the rear tray, both on paper source settings and properties.  I use too many different types of paper and sizes to make the cassette realistic.

Help please

ggoss