Preview is not a reliable viewer for anything but the very simplest of PDFs.
Thanks but that doesn't solve my problem since a lot of people will undoubtedly be opening the file with Preview. I can't just dictate what people will use. What's your viewer of choice, Acrobat?
You should always include a link to the FREE Adobe Reader with advice that best results will be seen using it when you distribute a PDF.
Of course you cannot control what others will use, but if you expect them to use Preview you need to dumb down the design accordingly.
Has this been solved? I am having the same problem.
The problem is Preview - it turns any box into a checkbox automatically. I actually can't find any information about it or how to turn it off. Here's what it looks like in Preview when I click the box, (just a square, not specified as a checkbox in InDesign):
And then when I specify the box as a checkbox, it seems to add another tick when it's clicked.
If anyone has any other information on it please let me know!
As above, the problem is using the wrong viewer. If it's going to be solved, it will need to be done by Apple in their viewer.