The second video needs to go on the same track as "Pirate de Caraibes.." in your screenshot (or lower) to use the chroma key, but I don't know why you don't have a video tab like this:



Is the app version 6.8.0 (Build 80027)? Tap/click on the gear icon, then Settings and scroll down to About PowerDirector.

YouTube/optodata

DS365 | Win10 Pro | i9-9900K (4.8GHz) | RTX 2070 | 32GB RAM | 10TB SSDs | 5K+4K HDR monitors

Canon Vixia GX10 (4K 60p) | HF G30 (HD 60p) | Yi Action+ 4K | 360Fly 4K 360°

The issue with Aliza's lack of video on a second timeline is the processor power or lack of support for same.
I have the same problem with my Galaxy tab 8 tablet, I get one video timeline, two layers strictly image/title/gif. Two audio timelines.
On my i-phone the same program gives me 3-4 video, more layers, more audio timelines. HP Envy Phoenix/4thGen i7-4770(4@3.4GHz~turbo>3.9)/Nvidia GTX 960(4GB)/16GB DDR3/7,200rpm/w10x64---
Canon Vixia HV30/HF-M40/HF-M41/HF-G20/Olympus E-PL5. Analog tape capture equipment.
https://www.facebook.com/B-Gill-Cyber-Studio-609762572849441

On my cellphone when I download the application I have the camera for the chromatic key. It works.
But on my chromebook it doesn't.

I want to desinstall and re install the application but I'm afraid of loosing my project that are saved on the application and not the cloud.

Do my project will diseappeard if I desinstall ?

You could back up the project files to say your pc or the cloud before doing the uninstal. I do not beleive that there is a packed project equivalent of the pc version of the software where the project is portable between phones or tablets. I beleive that a saved project in the cloud can be opened and edited on a pc. See this tutorial: https://youtu.be/fXSmOZgzmpM .