One solution I'm aware of is to add the following script to each page you display in the browser:

<SCRIPT ID=clientEventHandlersJS LANGUAGE=javascript>
document.oncontextmenu = function document_oncontextmenu() {return false;};
</SCRIPT>

>Hi all,
>
>i recently tried to embed IE on a form to act
>as a rendering tool for local html stuff
>(files, no web resources).
>
>No problem with it until i discovered
>a nasty problem i could not overcome.
>
>How to replace (or at least disable)
>the defaut IE left-and righ-click
>popup menus with your own.
>
>Help welcome!