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?


It's not a bug, it's just a missing feature. Originally the purpose of a PDF was just to emulate a printed page. Think of a PDF page as basically just a map with the exact location of certain characters. A PDF page doesn't even know where word boundaries are, much less paragraphs and columns. It is up to the artificial intelligence of the PDF software to recognize these things, but this is tricky business, and it's unsurprising that even the best PDF software does not always get this right. You may get different results in different PDF readers, however.

More recently, the notion of a "tagged PDF" has evolved, which allows for the insertion of 'guideposts' to help the PDF reader software understand the flow of text, so it doesn't have to rely so much on its own artificial intelligence. There have been some experiments in the direction of producing this with pdfTeX (see this question, but I don't think anything is quite ready for production-level work yet.

  • Thanks. I got a "your PDF generator sucks" comment from someone looking over my shoulder as I was playing around with selections, so it would have been nice to have a quick fix, but it's not that important. – zwol Dec 7 '10 at 20:32

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