When we install a Firefox Add-on Firefox delays 3 seconds to show “Install”
button on pop-up dialog that for a security measure, why should we wait for 3 seconds? with  a simple “about: config” hack we can disable this extension install delay and  No XPI Install Delay extension also does the same.

Firefox extension install delay

Disabling Extension Install Delay with About:config hack

1. Type about:config in address bar and go ahead by agreeing to warning “I’ll be careful, I Promise”.

2. Type Security.dialog_enable_delay in the Filter box and set its integer value from 2000 to 0.

3. Extension’s install delay is removed, restart the browser.

By using NO XPI Install Delay you can get the same result, disable or remove this add-on to get default extension delay setting back for Firefox. This extensions works from Firefox 2.0  – 7.0 a1.

Note : Mozilla doesn’t recommends this since it’s a bug ( It can happen, a user quickly or accidentally can  click “install” button without extension install delay, that’s why) . But if you’re installing add-on from trusted and secured addons.Mozilla.org why to wait? If you think “why not wait for couple of more seconds”  It’s up to you to decide.