Context menu and Mod Hierarchical flex grid problem

Hi
Can anybody help me ?
I try to show popup menu when the right mouse button is clicked on
ModHfGrid.
I see the popup menu but when I click any option the click event of
menuitem is not fired.
I try with button (not ModHfGrid) and everything is ok.

grid is as ModHFGrid control
Private Sub grid_MouseDownEvent(ByVal sender As Object, ByVal e As
FGridLib.DModHFGridEvents_MouseDownEvent) Handles grid.MouseDownEvent
Dim punkt As System.Drawing.Point
punkt.X = e.x
punkt.Y = e.y
If e.button = 2 Then
mnu_popup.Show(Me.grid, punkt)
End If
End Sub
Private Sub del_operacja_Click(ByVal sender As System.Object, ByVal e As
System.EventArgs) Handles del_operacja.Click
Dim lng_row As Long
Dim lng_col As Long
lng_row = Me.grid.MouseRow
lng_col = Me.grid.MouseCol
...................
End Sub