option has disappeared

This is hard to explain- When I browse websites such as Tomatoville, DG, PlantSwap, etc, in the past when I wanted to get out of a thread, I would click on the X and would get the message asking if I want to close the tab or close all tabs- I would choose just the present tab, and it would go back to the main window. that has gone away, and I get put out of the whole website, and have to reopen it. Can someone tell me what caused this? I'm wondering if it may have been a windows update. BTW, I am using windows7 home premium on a fairly new PC- Internet Explorer9 - (please don't tell me to switch browsers- been there -like IE9)