How can I put something (a mirror, for example) against the wall of a niche? It will only go as far as the original wall or it disappears.

Try "Material brush" on the top navigation bar, which is much convenient!

Oh! I never managed to chance the material inside the niche. I'll try again.

Hi, when you drag and drop furniture into the design, you could always use "CTRL" button to disable the auto snapping. So you could use press the direction arrow while holing Ctrl button.