I wonder why i am not warned when i accidentally close a window with many tabs opened .

I expect to be warned anytime i attempt to close a window with many tabs opened. i have had all my tabs closed accidentally(severally) just for this reason. Although its possible to recover the closed tabs, i find it lame that i am not warned about it.

I don't know if i need to configure it in my setting, or it wasnt just integrated into the functionality of the browser. This should be fixed!!