About modifying dual system default startup item settings

sudo gedit /etc/default/grub

The interface as shown in the figure will appear

2. my Windows The startup item is the third item , Set... On the sixth line of the pop-up page ：
GRUB_DEFAULT = 2; The original default 0 Change it to 2 Just fine .
There's a little bit of clarification here ,0 Express UBuntu System , Third Windows For system 2 Express , It depends on your startup options
3. After modification , The input terminal ：

sudo update-grub

Restart the system when finished , Enter by default Windows 了