Closing tab instances or single-tab windows not opened by javascript

Close this window (Using var objWindow = window.open(location.href, "_self"))

Steps to reproduce: click the above button

Actual results in Internet Explorer 7 and Internet Explorer 8 beta 1:
the window closes if there is only 1 tab opened or the tab instance closes!

Expected results according to MSDN2:
a confirmation prompt window asks, invites the user to approve, consent the closing of the window with the following text message:
"The webpage you are viewing is trying to close the tab.
Do you want to close this tab?
[Yes] [No]"

MSDN 2 Reference on close method:
Invoking the window.close method on a window not opened with script displays a confirmation dialog box. Using script to close the last running instance of Windows Internet Explorer also opens the confirmation dialog box.