Hi Doug, there is a setting for this: (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.tabs.closeWindowWithLastTab''' and pause while the list is filtered (3) Double-click the preference (or click the toggle button at the end of the row) to switch the value from true to false