Change in Mask Opacity changes Entire Video Opacity, not the mask
I added a single rectangle mask to a video (no other masks). I could see the video inside the rectangle, but not outside (expected).
I want this mask to fade in, so I set keyframes, then set the first keyframe to 0% opacity. The video inside the mask disappeared. As if I was changing the actual video opacity. I double-checked. I was changing the mask opacity.
What am I doing wrong?
