I had some difficulty doing this but found that you need to add the position effect FIRST and then apply the scale.
I created effects to position four videos on the screen at the same time. Then saved the effect chains out (In the effects window ->FILE -> Save Effect Chain to File)
You can copy the text below (between the lines) to notepad and save it is and "effects chain file"
Filename = "Shrink to Bottom Left.vdc"
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videopad
1
size=2&type0=34&preset0=Custom&data0=x%3Dvalue%253D0.500000%2526keys%253D0%26y%3Dvalue%253D0.500000%2526keys%253D0&type1=35&preset1=Custom&data1=x%3Dvalue%253D-25.000000%2526keys%253D0%26y%3Dvalue%253D25.000000%2526keys%253D0&fadepoints=0&speedchange=100&audiopitchchange=0&voll=0&volr=0&mute=0
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You can then open this effects chain file from the effects window in videopad.
Cheers
Chris