var enumerator = mgkWindowMediator.getEnumerator("navigator:browser"); var targetWindow = null; var tabCount = 0; while (enumerator.hasMoreElements()) { var cur = enumerator.getNext(); var ctabs = cur.getBrowser().mTabBox._tabs.childNodes.length; if (ctabs > tabCount && cur != window) { targetWindow = cur; tabCount = ctabs; } } if (targetWindow) { tabCount = getBrowser().mTabBox._tabs.childNodes.length; for (var i = 0; i < tabCount; i++) { var b = getBrowser().getBrowserForTab(getBrowser().mTabBox._tabs.childNodes[i]); targetWindow.getBrowser().addTab(b.currentURI.spec); } window.close(); targetWindow.focus(); }