I'm using pdf(la)tex to generate a document laid out in two columns. There are equations in both columns. I noticed that if I select text in the PDF (using either evince or Apple's Preview - haven't tried Acrobat) the selection doesn't reliably stick to one column or the other. The usual misbehavior is that clicking-and-dragging across an equation in one column causes the entire other column to become selected, but I've seen several other (difficult to describe) weird behaviors.
Is this a bug in pdftex, or a bug in the document class (IEEEtran.cls), or something I can correct with a package, or what?