compilation error with no logs (cause: scenario editor)

I encountered again a compilation error on a real time experience, with no error message allowing me to itentify the origin of the error. After a few hours of research, I finally found, by elimination, where the error come from. I'm sharing with you this error because I think it's a bug, in addition to supporting once again the need to have access to the compilation error logs in order to be able to identify the problem.

It seems to be an error with the scenario editor. My goal with the scenario I wrote, was to script a button so that each time I click on it, its parent is hided. I've already used this same scenario phrase in another act where it worked.

there is a picture of my scenario, the last sentence cause the build error. ("each time Close is clicked do web viewer 3D hides")

@NK @DN