User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.12) Gecko/20080201 Firefox/2.0.0.12 Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.12) Gecko/20080201 Firefox/2.0.0.12 Here is a super-short and sweet test case: <div>A</div><div style="display:none">B</div><div>C</div> Put that in a .htm file, open it, select the "AC" text, copy it and paste it in a text editor. You will end up with "ABC". The first time I noticed it was at the provided test url, where you use checkboxes to get a dynamic list of which Windows updates you need to download. I had selected the right list for me and tried to copy it, and noticed that the clipboard contained the WHOLE list. Is this "working as intended" behaviour, or is it a bug? Reproducible: Always Steps to Reproduce: 1. Try the 3-div test case Actual Results: Hidden elements on page were copied into clipboard; things that were not meant to be seen and which were not visible on the page. Expected Results: Hidden things are hidden for a reason, they shouldn't have been copied.

Sorry, thought I had searched quite well but turns out the bug had been reported 8 years ago(!). Well, that's a long time ago so I'll resort to manually checking what I have copied and removing what should not be there.