Sys Tray Popup Menu Problems

I seem to have problems on WinNT after I put an icon into the System Tray. When the user right clicks on the icon, a popup menu gets displayed. The only probelem is, in order for it to go away they must select something from the menu, clicking outside of the menu leaves it open. It works fine on Win98, and I know my code is right. Any suggestions? Thanks.

i think before you popupmenu you must setfocus to menu's owner form
just like these

Private Sub cSysTray1_MouseUp(Button As Integer, Id As Long)
If Button = vbLeftButton Then
Me.SetFocus
PopupMenu mnuTray
End If
End Sub

Hi, all
I am lumine
nice to meet you

Thanks for the info, but in order to set the focus to the form it must be visible, otherwise you get errors. And in this case, I can't have the form visible.