How to configure "Open All in Tabs" in Firefox without closing existing tabs?

From the past few months I have been using Firefox and have completely removed Flock for my general browsing. But I was facing one big problem with Firefox - When I used to click on "Open All in Tabs" in a bookmark folder, it closes all the existing tabs.

I was wondering to find a fix for this and today I found it.

Here's how you can disable it.

1. Open a blank tab, and type about:config in the address bar.
2. Find the browser.tabs.LoadFolderAndReplace setting, and double click it to change it to false.

This will keep it from killing all the tabs you already have open. You will have to restart firefox to get it to take effect.