Animated object disappears from rest of my project when I apply a new fill color

I'm having issues with an animated object in my project that I'm hoping I can get some guidance on.  The basis is I'm working out of a template and there's this animated line that I'm trying to change to black.  I opened the indiviual asset within my project space and applied a fill to the adjustment layer (refer to image) and it shows that the line changes to black but when I go back to my main project timeline it's gone, as in it disappeared.  Is there something I'm doing wrong?  I'm also a beginner in after effects so I'm unaware of a lot of the functions.  If anyone has advice please let me know, thanks!