BOM tree is not showing the required input quantities for a output product


Can someone help me with the concept of BOM tree report which is applied to a product variant? As per my understanding, BOM tree calculates the quantity of input products which are required to produce the quantity of output product to which we apply this BOM tree.

In tryton demo, It seems the BOM tree wizard is not displaying the required input products quantity when I select a BOM and enter the quantity of the output product. Is it a bug or am I doing any mistake?

The BOM of the only producible product in the demo site is empty:;name="BOM"&views=[385]

Indeed it is a bug in the web client: Issue 8188: One2Many display fails if field is null - Tryton issue tracker
You should see the error in the JS console.