Add props at partition level so they move with the cabinet

Add props at partition level so they travel with the cabinet, then fine-tune their position in the furniture layer with X, Y and Z offsets.

1. Props added at partition level move along with the cabinet when it is moved.

   ✓ 已于 2026年10月9日 在产品中核实

2. The position of the props can then be adjusted in the furniture layer using X (left/right), Y (up/down) and Z (back) offsets.

   ✓ 已于 2026年10月9日 在产品中核实