Sorry, I do indeed mean the Entry Editor. I rashly overwrote my previous installation, but on an older machine I have version 2.10. There I had the Entry Editor set up so that the first page displayed, in order, Abstract (several lines), Author (1 line), Journal (1 line), Key, Month (1 line), Number (1 line), Pages (1 line), Title, Volume (1 lijne), Year (1 line) , Bibtexkey (1 line), If I resized the Entry Editor pane some fields would disappear from the bottom of the window but a scroll bar would appear on the right. My preferences for which fields to display were correctly imported when I installed Version 4 – the difference is that the fields seem always to have equal sizes, determined by evenly dividing the window height, with the scroll bar appearing when every field shrinks to one line. The previous method suited me, and I’d got used to it, but tempora mutantur, nos et mutamur in illis.
Lest I sound grouchy, let me wind up with sincere thanks to all who developed and maintain JabRef: it is a superb tool.