Mask not applying in Final Cut Pro

Hello, I am very new to these programs so my apologies if this has been discussed before and/or is a rudimentary fix. I have downloaded BCC +Looks. I apply it to a clip. I click on Mocha Mask and Mocha opens. I apply my mask and track it.

Now, I was under the impression when I go back to FCPX and click “View Mask/Matte” under the Pixel Chooser, my mask would show up. What shows up is just a blank white screen, as if there is no mask.

Has anyone else had this problem? Any and all help is greatly appreciated!

Hi, do you want to isolate Looks color effect only to a specific area of the clip? Here’s the tutorial that can help, where Ben shows how to do a similar thing with Prism effect