To change the value just double click on the row and enter your preferable value as shown in above list.
Firefox is a great browser , I love it, but some inbuilts features may irritate you.
Here I am giving you a guide to remove such one inbuilt feature.That is close button on every new tab.
Some people can’t stop themselves from clicking the little close button at end of tab.So here are steps to remove the close buttons from the tab.
1. Open new blank tab and type about:config in address bar and press enter.
2. In filter copy-paste this browser.tabs.closeButtons
3. you should get the field in column “Preference name”.
4.Now set the value as per following table and needs.
To change the value just double click on the row and enter your preferable value as shown in above list.