This extension works like Mac's Expose feature, except that it concentrates on showing a thumbnail overview of all of one's tabs (which can then be clicked on to choose a particular tab). Inserting the following right before "" in the file "xpose.xul" in the "/extensions/xpose@viamatic.com/chrome/chromeFiles/content" directory will allow one to invoke this helpful extension via a key command (here as shift, ctrl (command/apple key on Mac), and X) rather than needing to rely on clicking the small icon.