Just trying to take a guess at it so I looked at my settings because my display doesnt do that.
click on user control panel, edit options, page down to thread display options, there is a thread display mode.....i have linear - oldest first
what does your say? if its different, try the setting i have and let me know if it works
"Yesterday I was clever and tried to change the world. Today I am wise and try to change myself." -Rumi