We added the capability to click RadMenuItem with right mouse button for RadContextMenu but this affected RadMenu also. Last week we fixed this issue so if you try the Latest Internal Build you will see that now right click affects only items that are in RadContextMenu (RadMenu is not affected).
Let us know if you need more information.
the Telerik team
Do you want to have your say when we set our development plans? Do you want to know when a feature you care about is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items