Disappearing Items

@Hoshi_JiWoo Have you checked that you are using the 'DIY Rollup Mural' (there's also the 'DIY Garage Mural' versus the 'Community Canvas'? The DIY Murals are interactive and can be found under Activities and Skills, the Community Canvas is decorative.  When I tried placing the Community Canvas it will disappear in live mode if your walls are in cut away or down, it will display if the walls are up. Here's what they look like in buy mode:

Here's what the look like in live mode (excuse the darkness, it's night time in this particular save where I was comparing them).

Walls up:

Walls in cutaway (looks similar to walls down):

Other than that, the DIY works fine for me, you can see here my sim interacting with it (walls are up again): 

The community canvas can't be interacted with, sims don't appear to be able to view it (though it seems not all wall decorations, which is the category this is under, can't be viewed). 

Best regards,

Jennifer