Creating Fillable PDFs: moving fields

I've been using Adobe Acrobat X to create fillable PDFs for a couple years now.  Recently however, I noticed that I can't move the fields in the manner I used to.  I used to be able to move the fields just a TINY bit but now when I click to drag the fieldbox it "jumps" around the page -- I'd guess about a half inch at a time.  I'm having the same issue when trying to resize the field boxes as well.  Has anyone else had the same issue, or knows what is going on?