I recently enabled vertical tabs in Microsoft Edge.
The problem is I accidentally close all my tabs now. I searched for a way to be asked before closing a window with multiple tabs like other browsers, but I had no luck. Well until I found a way to enable it with experimental features.
To begin open Edge and type the following in the address bar:
edge://flags
This will take you to the Experiments page where you can enable experimental features. One of the features is the “Ask Before Closing Multiple Tabs”. Select the dropdown and change the value from Default to Enabled. Note that doing this will restart all instances for Edge that are running.
Once this is enabled you can use the Appearance section under the Settings page to enable this feature.
Now when you attempt to close Edge with multiple tabs open you will see this warning.
Enjoy.