2. Enable Firefox in Quick Hide IP setting.

  Start Firefox, and then start our software Quick Hide IP.

  It is not a must to keep Firefox run when change Quick Hide IP's setting. 

     But I think it could be easier to understand.

     Now, in Quick Hide IP's setting dialog, select Firefox checkbox.

  After clicking "OK" button,a dialog is prompted with warnning message

 "Firefox should be closed to change its setting. Do you want to close Firefox?" 

This is because Firefox is running now, it should be closed to change setting. Click "Yes".

3.Check Firefox setting

Now, Firefox should be restarted automatically.

Click"Tools" menu's "Options" menu item, the Firefox option dialog is shown.

Then switch to Network TAB, press "Setting..." button.

In the connection settings dialog, "use system proxy settings" should have been selected. This is the key for Quick Hide IP to work for Firefox. The setting refer to that, Firefox will use Windows system proxy setting.