Firefox undo close windows when multiple tabs open

Question

When closing with firefox while having multiple tabs that confirm dialog comes up. Theres a box that ask if you would always like to close when more then 1 tab is open. I accidentally checked that off. How do i undo that?

Answer 1

Try:

Tools > Options > Tabs > Warn me when closing multiple tabs.

Answer 2

You can re enable is using about:config

• Open a new tab with blank page and type about:config
• Accept any security warnings and type browser.tabs.warnOnClose and make sure that its true.
• If false, double click and make it true.

Thats it.