Come on Ecca, even I can find it
Right click over the clip, the 4th one down is 'video event pan/crop'
4th blue highlighted item is 'source'
click the + to get the drop down, 2nd one is 'stretch to fit'
click on that, you get the drop down, choose no.
Honestly, I send you here so I can stop answering your questions, and I still end up answering them
Track 1 takes precedent over track 3 (track 2 is audio) so you only see track 1, unless you make the picture in track 1 smaller, or make gaps in it, in which case you can see 'through' it or either side of it, to track 3.
Imagine you are looking down onto the tracks, if track 1 is on top, it obscures what is in track 3 underneath, unless the pic in track 1 is either smaller, so you can see track 3 on either side of it, or has gaps in it, in which case you would see track 3 through the 'windows'.
Actually I have been doing this as I go along, to get the picture in track 1 to shrink but stay 'whole' I seem to need to have stretch to fit set on 'yes'. Otherwise I just reduce the amount, as in proportion, of the picture in track 1, not the size of it, if that makes sense.
Having played around a bit more, it works like a zoom, you can do all sorts of combinations.
Gillian