STEPS TO REPRODUCE
1. Launch popVideo 3
2. Navigate to Toolbar > Import File, load a mov file to program
3. Go to Playbar, set Mark In/Out to 00:01:400 – 00:04:500
4. Click “Stop” button
5. Go to Edit tab, click “Chroma Key”, and then open “Please choose a color” panel
6. Click “Pick Screen Color” button, click black background in Viewport

ACTUAL RESULT
Nothing changes

EXPECTED RESULT
Keyer effects for black can be executed correctly