ithinc：下面这个脚本放uc里执行一下就可以恢复原来版本的行为了，很小的改动。

eval("gBrowser.warnAboutClosingTabs = " + gBrowser.warnAboutClosingTabs.toString().replace("!!aAll", "true"));

回到原帖

ybbao：没明白，怎么放在UC里面？回到原帖

kmc：还真的给灭了
https://bugzilla.mozilla.org/show_bug.cgi?id=772319

新增了隐藏的pref：
browser.tabs.warnOnCloseOtherTabs;false回到原帖

//关闭所有标签页
gBrowser.removeTabsBut = function removeTabsBut(aTabs, bTabs) {
    aTabs = aTabs ? "length" in aTabs ? aTabs : [aTabs] : [];
    bTabs = bTabs ? "length" in bTabs ? bTabs : [bTabs] : [];

    if (bTabs.length > 0)
      aTabs = Array.filter(aTabs, function(aTab) Array.indexOf(bTabs, aTab) == -1);

    if (this.warnAboutClosingTabs(true, aTabs)) {
      if (Array.indexOf(aTabs, this.mCurrentTab) > -1)
        this.selectedTab = bTabs[0] || aTabs[0];

      let count = 0;
      for (let i = aTabs.length - 1; i >= 0; i--) {
        this.removeTab(aTabs[i], {animate: true});
        if (aTabs[i].hasAttribute("removing"))
          count++;
      }
      this._lastClosedTabsCount = count;
    }
  };
gBrowser.removeTabsBut(gBrowser.allTabs, gBrowser.mContextTabs);
gBrowser.removeCurrentTab();