How To: Disable the Context Sensitive Menu

You can disable the SVG Viewer Context Sensitive menu by trapping events in an element.
Example:
Make a 0% opacity rect the size of the SVG that would receive and preventDefault() all appropriate events.

Note that our popup menu honors platform UI, so there are some differences between Mac and Win in terms of which events to trap for.

<svg>
<script language="Javascript">

function handleIt(evt)
{
evt.preventDefault();
}
</script>

<g id="square"   onmouseup="handleIt(evt)"  transform="translate(50 50)">
<rect x="0" y="0" width="100" height="100" style="stroke-width:2;fill:yellow; stroke:blue"/>
</g>
</svg>

http://support.adobe.com/devsup/devsup.nsf/docs/50526.htm