Shell Context Menu

With the help of some samples (from Codeguru, CodeProject etc..), I''ve written a small DLL to display my own popup inside the Explorer context menu (like WinZip does, for example). My problem is when I click 1 times on the File menu, my Popup appears normaly, but when I click again a new entry is added, and the popup appears 2 times ! etc ... What''s wrong with it ?? I know the problem comes from the QueryContextMenu (which creates the popup) but I can''t find any solution. I tried to delete myself the handle and recreate it, tried InsertMenu and InsertMenuItem (maybe misused?)... Thanks for any help