'''Check for updates, but let me choose whether to install them''' opens a small internal popup window that allows you to not accept the update download & installation. That small popup may be diverted to behind the main browser window by any keyboard or touch pad action, or any mouse action; when that happens Firefox only waits ''like'' 30 seconds for a response before proceeding to begin downloading the update. ''Very easy to miss even seeing that small popup appear, other than a "flash" of a 2nd Firefox window indicator appearing in the Windows Taskbar and then disappearing in 30 seconds.''