reset_panorama.js

/* Run this from your error console */
var Cc = Components.classes;
var Ci = Components.interfaces;
var ss = Cc["@mozilla.org/browser/sessionstore;1"].getService(Ci.nsISessionStore);
var wm = Cc["@mozilla.org/appshell/window-mediator;1"].getService(Ci.nsIWindowMediator);
var winEnum = wm.getEnumerator("navigator:browser");
while (winEnum.hasMoreElements()) {
  var win = winEnum.getNext();
  ["tabview-group", "tabview-groups", "tabview-ui", "tabview-visibility"].forEach(function(v) {
    try {
      ss.deleteWindowValue(win, v);
    } catch (e) {}
  });
  for (var i = 0; i < win.gBrowser.tabs.length; i++) {
    win.gBrowser.showTab(win.gBrowser.tabs[i]);
    ["tabview-tab"].forEach(function(v) {
      try {
        ss.deleteTabValue(win.gBrowser.tabs[i], v);
      } catch (e) {}
    });
  }
  win.TabView.init();
}