在应用商店搜索 No Topleft Hot Corner 并安装，设置下就好了
具体问题可参考以下网站：
https://unix.stackexchange.com/questions/196541/remove-disable-hot-corner
https://askubuntu.com/questions/1065973/how-can-i-remove-this-applications-icon-which-does-nothing-on-clicking-either