Hi Mark, could you check whether the following setting was turned off (set back to false): (1) In a new tab, type or paste '''about:config''' in the address bar and press Enter/Return. Click the button accepting the risk. ''More info on about:config:'' [[Configuration Editor for Firefox]]. ''The moderators would like us to remind you that changes made through this back door aren't fully supported and aren't guaranteed to continue working in the future.'' (2) In the search box in the page, type or paste '''browser.altClickSave''' and pause while the list is filtered (3) If the preference has a value of false, double-click it (or click the Toggle button at the right end of the row) to switch the value to true (This preference is mentioned in the Links section of "[[Use mouse shortcuts to perform common tasks in Firefox]].")