C# winform Menustrip merging problem

class MDIFormMenu: System.Windows.Forms.MenuStrip
{

}

class ChildFormMenu:开发者_运维百科 System.Windows.Forms.MenuStrip
{

}

I used MDIFormMenu on MDIForm set MainMenuStrip property and ChildFormMenu added on ChildForm. It is failed to merge.

If I used same class menu on both form it works.

Please help me, what am I doing wrong?

The ChildFormMenu must be derived from MDIFormMenu. This behavior is perhaps by design.

class ChildFormMenu: MDIFormMenu
{

}