>>It seems that Ebay IT guys have failed to reinsert the line of programing needed to
>>highlight an item title after the item has been selected and viewed.
No, they inserted code that adds search result ranking information (position in returned search results) to the item URLS in the search results. That ranking changes all the time, causing the item URLS in search to not match the ones for visited item pages in browser search history - thus those visited links are not highlighted by the browser.
The addition of the parameters to the URLS was intentional, and I can only assume the the unintended? consequence of visited links functionality breaking as a result was due to tunnel vision. It isn't going to be "fixed", and there is no realistic workaround without re-writing parts of the browser code, or creating an addon to manipulate browser history (if even technically doable due to browser security), or using those approaches or an add-on user script to rewrite search result pages and change the item URLS on the search result pages to a consistent format without the variable rank, hash, and tracking junk appended (which would stay the same, match browser history, and result in highlighted visited links)
Any realistic workaround would involve stripping that data from the search result item URLS as the results page loads. Stripping it out after the fact from browser history (if even possible because browser security), won't work because new URLS (same item different result ranking) on search result pages wouldn't match the stripped search results in history. That ranking information isn't needed for any item page loading functionality or anything we care about, so stripping it off is a possible approach. A GreaseMonkey script can pretty easily do that as long as the data being added to the hash portion of the search result item URLS isn't too much of a moving target.
However, eBay item URLS are a moving target. There are so many variations on parameters added that they almost never match whatever is in browser history. For example, I use the Redirector addon to add ?nordt=true&orig_cvip=true (or &nordt=true&orig_cvip=true if any parameters are already present) to all item URLS that load to prevent eBay redirecting me to similar items when the item is an ended listing. That addition breaks the visited link functionality, just as eBay's added tracking and ranking junk does. eBay also presents item URLS with the item title as part of the URL - that also won't match the item URL containing only the item number.
So some of the stuff can be stripped without losing desired functionality (the tracking, ranking, hash junk), and some not (the ?nordt=true&orig_cvip=true stuff I intentionally put there to control what gets loaded, and probably others I can't think of at the moment). That complicates the script logic needed a lot. Still doable, but not on my radar.
