To reproduce:

1. Add a RadMenu with one item which has one child item.

2. Click on  "radMenuItem1"  then  will appear  "radMenuItem2 " . - Keep ("radMenuItem2") open and  do not click on it  - 

3. Go out of the form and click on empty area .

4. Return to the menu and just move mouse over the "radMenuItem1"  and it will appear "radMenuItem2" and also move the mouse over the "radMenuItem2" and keep it open . ("do not click on menus")

5. Go out of the form and click the Show Desktop button on the bottom right of the screen

6. Now you can see the problem ,  the menu has not closed



Workaround:

override the WndProc method in your Form with the following:



protected override void WndProc(ref Message m)
{
    if (m.Msg == NativeMethods.WM_SIZE && (int)m.LParam == 0 && (int)m.WParam == 1)
    {
        PopupManager.Default.CloseAll(RadPopupCloseReason.AppFocusChange);
    }

    base.WndProc(ref m);
}

if the above does not work, you can try the following:

private void Form1_Deactivate(object sender, EventArgs e)
{
  PopupManager.Default.CloseAll(RadPopupCloseReason.AppFocusChange);
}