HD converting to 16:9 letter box

This is something that baffles me. I did some captures from an HD camera in FCE and did some rough edits creating 2 or 3 sequences will different scenes and closed out of the project. A co-worker did a capture using SD and 4:3, and did his work. When I went back into work up a video with my previously captured footage and sequences into a final edit, the browser for doing ins and outs was seen as 16:9, but the timeline browser was showing a letterbox set up and previous titles that I had added were spilling out onto the letterbox. I did not change any settings when I went back into FCE, and the only setting change I am aware of that my co-worker did was in the easy setup for capturing his video. Why am I getting a letter box in the sequence browser now, when previously I was seeing it 16:9 fullframe? I also imported some other video also HD 16:9 and it worked up as fullframe HD 16:9.
I didn't check the timeline sequence settings, but would they change if previously it was 16:9 fullframe? Any suggestions would be wonderful....thanks..

jerry

sioux city