Thank you for your quick reply.  Unfortunately, It does not reselect the highlighted area when I click on it, and when I reselect it by clicking and dragging, and then click delete, it does not delete it.  However, when I opened the document again just now, the highlights do show up in the comment section, and if I right click, I can delete them.  It doesn't tell me which "comments" I am deleting, but at least it does allow me to delete them.  I think it may have something to do with the links in the document, and the fact that the titles (which is what I am trying to highlight selectively) may be somehow attached to the links.  At any rate, I have not had problems with other PDF documents, so I think this is an anomaly.  Thank you again.