Hi
If I understand correctly you want one clip to play in the top half of the frame with the other clip playing in the lower half of the frame.
The way it should work is........
Start by loading both clips.
Place clip 1 on the main sequence line (Video track 1) and place clip2 on the overlay track (Video track 2). Line up clip 2 exactly over clip 1.
Right click clip 2 (which overplays clip1) and select "Current effects properties"
Click the down arrow in the top box and from the menu select "Crop"
Click the "Add button"
Set X1 = 0
Set Y1 = 25%
Set x2 = 100%
Set Y2 = 75%
Clip 2 will now occupy the middle of the screen and be 1/2 height of the frame.
Grab the red rectangle in the centre and manually position it over the portion of the image you want to show in the frame. This will change the values but this is OK. If you want to fix the aspect ration click the relevant radio button.
Click the down arrow again and Select "Motion"
Click "Add"
Assuming you want Clip 2 at the top....
Set Position x% at 0%
Set Position y% at -25.00%
Clip 2 will now be at the top of the frame.
Repeat for clip 1 on the main sequence line
To position the frame set the y position to 25.00%
The two clips should now be one over the other
However although both clips seem to be positioned correctly in the right hand preview window , the thumbnails of clip2 under the left preview pane as well as on the sequence line only show as the landscape icon although the left preview itself displays the half images of both clips individually correctly.
Playing the complete sequence though continually shows the "Building Preview" message.
So I think there may be BUG here somewhere.
I would be interested if anybody finds similar behavour
Nat