Textwrangler Open File in New Tab

I just become a Mac user and I've been looking for a decent free code editor, thus I found Textwrangler. However, I like it a lot, I only have one problem with it. How does one open a new file in a new tab rather than a new window? I open a directory with it and have the tree, but each time when I click on a file it closes the current file I am viewing and opens the new one. Is it possible to have things open in a new tab as when you one a link in a new tab in Chrome or more exactly how you open a new file in Notepad++ on Windows.