This is all he's after Jeff.

When you open a post window and the cursor is in the pane, the Post button is highlighted with a black outline. If you hit tab at that time focus jumps to the Post button and you see the dashed box around the text of the Post button.

Hit tab again and that disappears and the Preview button become highlighted with the dashed box around the text of the Preview button.
What ever you did yesterday made both the Post and Preview button have the dashed box on the button text simultaneously. But when you tab from the post window, the Post button now expands and the black dashed box becomes red. Tab again and the Preview does the same to indicate it is now in focus.
The images were a snapshot in IE 6.