Just to clarify you are referring to the 'Body' field and not the subject field? If you are you are able to adjust it by selecting and dragging the bottom right hand corner of the field.
It may be a browser related issue, what browser are you using? We recommend that you clear the cache and cookies on your browser or use an incognito/private window.
Yes it is the Body window I want to enlarge, I cant select anything on the body window at all, it seems fixed. The browser is microsoft edge win 10. I have firefox, so ill try that also.
Oddly as I type this reply I can see bottom right triangle to pull the body down. This is what I am missing on the save and send window!