Help . background generator don't work anymore

Hello, this morning I realize that the background generators don't work anymore in my FCPX, the solid ones (whites, blue,...). When I put a solid background generator on the timeline, it is transparent, as if it was deactivated. All the other generators are running fine (grunge, metal,...) ! I checked all preferences / set up, nothing changed ! I am completely lost, if anyone has an idea where it might come from ? Tis

Start by trashing prefs. Can you post a screenshot of the timeline and viewer maybe with the generator on top of video.

Ho Tom, first things I have done is to trash the prefs, no change.
I dattached a copy of the screen. I create a new project, took the white generator and put it on the timeline, black screen... It drives me crazy !

Try reinstalling the application.

Well yes I think it's the only wise thing to do

Yep, trashed FCPX and download again from the AppStore, it works now...
Strange anyway !

Seeing quite a few reports of bits and pieces that appear to be missing in the application. Could I ask which version of the software and the OS you're using, and if you updated them recently? Thanks.

I have upgraded to OS X Capitan 10.11.2 a week ago, and FCPX 10.2.2 more or less at the same time.
I didn't notice this issue immediately since I didn't have any project with a solid background !

Thanks.