3、Enter the new entrance → Enter the new world → Enter the door → It is important to keep in mind that it is necessary to enter the new market, to move to the right and to move to the right.终端命令强制锁定“居中”模式（高级用户）

当图形界面选项异常失效、Finish the main body, change the information, use the settings.

Section 1步：Return to the main road and then move to the next step（Ctrl+Alt+T），执行：gsettings get org.mate.background picture-filename

第2步：锁定显示模式为居中执行命令：gsettings set org.mate.background picture-options "centered"

Section 3 steps: gsettings set org.mate.background draw-background false && gsettings 设置 org.mate.background 绘制背景 true