Windows provides a special type of menu item, called a separator, that appears as a horizontal line. You can use a separator to divide a menu into groups of related items. A separator cannot be used in a command bar, and the user cannot select a separator.
When a menu contains more items than will fit in one column, the menu will be truncated unless you force the line to break. You can cause a column break to occur at a specific item in a menu by assigning the MFT_MENUBREAK type flag to the item or using the MENUBREAK option in the MENUITEM statement. Windows places that item and all subsequent items in a new column. The MFT_MENUBARBREAK type flag has the same effect, except that a vertical line appears between the new column and the old. If you use the AppendMenu or InsertMenu function to assign line breaks, you should assign the type flags MFT_MENUBREAK or MFT_MENUBARBREAK.