http://www.xulplanet.com/references/elemref/ref_tabbrowser.html#prop_addTab

addTab ( url )

Return Type: tab element

Displays a new tab loading the specified URL as the document. The row of tabs will appear if needed.

I just found out that I can add a sideBar and tabs to mozilla…I’ve been trying to figure it out for a while now. Thanks, XULPlanet.