letterbox moves when I scale the image

[Thaxter Clavemarlton]

a. Create a new video track directly ABOVE the clips you want to mask (I’ll call it V2).
b. Apply the “Slug” (or a black Matte Color) on V2.
c. Apply “Mask Shape” Filter: (Video Filters > Matte > Mask Shape) on V2.
d. Set up the Mask Shape Filter in the Motion Tab: First click “Invert”. Then adjust the sliders to create the exact mask size you want.
f. Now you can move the V1 clips any direction you want and the mask will stay “fixed” of V2.

[Sean Lander]

Yes because motion effects always come before filters you will need to apply the BASIC 3D filter ABOVE
the widescreen filter. Then do your scaling with this.