More than once I have accidentally clicked the close button on the top right of my browser window. In the past this was not a problem because I had 'warn when closing multiple tabs' checked (I always have multiple tabs open). Firefox would shoot me a nice little warning and I could click cancel and not lose all my tabs. For some reason FF has stopped giving me a warning message, even though I still have 'warn me when closing multiple tabs' checked. I'm not sure when this started happening, but it has been going on for a while. I am running FF 22.
I have tried (unsucessfully):
*unchecking the checkbox and restarting FF, then checking the box it again and restarting
*starting in safe mode
*clearing cache and restarting
*restarting my computer
Does anyone have some ideas of what else I can try or know how I can get my nice little warning box back?