This is a behavior of IE.

Basically, if you right click on a link to open in a new window, if that link as a target name, that target name will be broadcasted in your new window. So, you end up with the new opened window to have the same name as the target name of the link you clicked on. So, for example, on the right side, if you click on a message, you get the message in this window. It has a name and it is used for the redirect. But, right click open in a new window, and that target name is now broadcased in your new window.

Firefox and Google do a good job in managing that. Basically, they make that target name disappear from the click.

To work around that, the page you are opening, should clear its window name:

window.name=""

By that, you are assuring that the page called as is would still have no name. But, if a user ends up on that page from a right click new window with a target, that will clear it from memory.