This annoying behavior pops up when browsing sites like reddit, which has an option to display a toolbar with the post title, quick access to comments etc. I frequently open several links in different tabs then read and close them one by one.
Expected behavior is for stackoverflow to either wait patiently for me to close the frame or close it quietly in the background. Actual behavior involves rudely dismissing anything else I was doing the moment it finishes loading and becoming the active tab. This usually leads to me closing the tab to go back to whatever I was doing.