Thanks for that link; that thread seems to be more about forms, whereas my issue is when I add a text box for adding annotation of my own.

I will attend more closely to sources of the PDFs; I know it's happened from more than one source, and as I mentioned i THINK it's always happening lately, but I'll be more attentive.

Still interested in hearing from anyone who may have dealt with this particular text-box-resizes-to-single-line glitch.

UPDATED REPORT: Before downloading Reader (which, I recall, also messed with Safari's PDF viewing), I decided to try using Acrobat, which I also have. When I clicked into a text box I'd made in Preview, instead of going to the "one-line" mode, it filled the text box with RED! But when I made a new text box with Acrobat, then left it, and returned to edit the text, then double-clicking placed the cursor, as it should, no problems. So it seems to have to do with Preview's text box creation. (at least on this PDF; still will attend to different sources)

Last edited by JimCummings; 12/21/12 08:14 PM.