敬请参考：
https://zhuanlan.zhihu.com/p/585280693
gsettings set org.gnome.shell.extensions.dash-to-dock click-action minimize-or-previews
这个设置
总共有几种选项
'skip'
'minimize'
'launch'
'cycle-windows'
'minimize-or-overview'
'previews'
'minimize-or-previews'
'focus-or-previews'
'focus-minimize-or-previews'
'quit'
minimize是点击最小化，再点一次打开。
focus-or-previews：如果该程序无focus，则获取focus并显示在上层；如果该程序有focus，则显示多窗口preview；如果没有多窗口则啥也不做
focus-minimize-or-previews：一个程序启动了多个窗口时：focus-or-previews；只有一个窗口时：minimize