Premiere Elements Video size

Hi, I made a video in PE that I use as a closing for all my other PE videos.

I must've hit a wrong setting somewhere because all of a sudden that PE video doesn't fit neatly when dropped into another PE video.  It is much narrower and doesn't fill the screen, such that I have to pull the corners to make it fill and then lose much of the content.  Where would I have 'resized' my videos?