Yes, This has been a problem for a long time. I agree with Jon's comment. It is not an O/S problem. The developer just does not want to do it.
My work around is to copy the highlighted search results into Word (make sure you retain formatting and paste in using source formatting.) Then use Word's Search and Replace function to mass change the highlight. I have created a quick video to help with that. I could not find an upload function so here is the link to it. Will leave the link active as long as I have this computer. Word Mass Highlight Change.mp4
Hope this helps someone.