Firefox just updated itself to version 16.0.1. Now, when attempting to close multiple tabs, I get the "Confirm close" warning even though the "Warn me when closing multiple tabs" option is unchecked. I tried checking that option, confirming the change, then unchecking that option again & confirming the 2nd change, too. This has made no difference. Firefox is not obeying the option setting.

The problem didn't occur before the update to 16.0.1 but did occur in the first session afterwards & has persisted since.