Hi. In general settings screen, this option does not run. I attached the screenshot. It is said that icedragon warn you when quitting but it doesn’t warn while closing last tab. Thanks.
Hello serkansoyad , thank you for taking your time to report this issue, i have tested it a bit and looks like it works ok for me, try to have more pages opened, if you have one page the pop-up may appear only once!
Namely, “warn when quitting” accrues when you try to close the whole program by clicking right top X symbol, instead of the last tab. But it would be better if it warned while closedown of last tab. Thanks for your interest.