Opacity in an animation doesn't stick I'm just getting started with Final Cut Pro X and I'm following this video for a slide out animation: 
                
            

I have a background square for my text as the Text moves to the right. If I set the opacity to 80%, the background looks how I want when there is no animation. Once the transition is animating though, the background is opaque and not transparent. Is there a way to get around this? 

Thanks!
I think I know what’s the problem is. 

The compound clip isn’t working that way because you have probably a “Solids” generator in it. 

Ignore the step of generating the compound clip and build the sliding box and text on top of the main timeline. That should work as you want.