Yahoo Toolbar

Just had a taste of my friend's blog on User Interfaces and that got me thinking.
This i sumthing that i am good at. So i have started givin more attention to the scores of little buttons and tabs that we click everyday, the textboxes in the forms we fill without a second glance.
So let me take you to my first post on my newfound interest:

Have you ever installed the yahoo toolbar on IE and tried opening sumthing in a new tab.
Just suppose you are reading something on a web page and you find a link in it interesting enuf to be read. so what a normal guy would do is right-click, select open in new tab and continue browsing the current page. Then you go through the new link that you opened once you are done with this page.
Now if you do this on IE with yahoo toolbar installed it takes you to the new tab directly. the page you were browsing goes out of ocus and you are looking at a page that is being loaded.
Now why would anybody open it in a new tab if the new page is what they wanted to see.
Firefox behaves he way i said i expected it to.
Now how did yahoo miss this part??