A separate is used to separate categories of menu items. We can add a separator to a menu control by using <Separator /> tag.
We
can also ass sub menus and sub menu items using the MenuItem tag within
parent a MenuItem tag. The following code adds a separator and sub
menus and sub menu items to the menu.
<Separator/>
<MenuItem Header="Sub Items">
<MenuItem Header="Child1 SubItem" IsCheckable="true"/>
<MenuItem Header="Child2 SubItem" IsCheckable="true">
<MenuItem Header="GrandChild2 SubItem" IsCheckable="true"/>
</MenuItem>
</MenuItem>