Today, I was looking for a method for customize contextual menu in excel. I found this topic useful:
http://www.rondebruin.nl/win/s6/win001.htm
However in the following XML code, this snnipet idMso="ContextMenuCell" doesn't work under any circumstances. I spent several hours looking for a table object id for idMso.
<customUI xmlns="http://schemas.microsoft.com/office/2009/07/customui">
<contextMenus>
<contextMenu idMso="ContextMenuCell">
<dynamicMenu id="MyDynamicMenu"
label= "My Dynamic Menu" imageMso="HappyFace"
getContent="GetContent" insertBeforeMso="Cut"/>
</contextMenu>
</contextMenus>
</customUI>