If you are trying to add a product to the inventory and after saving the item, and it is not showing in your inventory, you will need to check under Inventory -> Feeds if the supplier has been hidden.

If the supplier has been hidden under Feeds, the product will NOT show in the inventory.

An example of where this could occur is that you may not use the WHOLE Metagenics range so you would not switch on the Metagenics feed. You would add in manually the handful of products you prescribe. 

If you go to set the supplier as Metagenics, the items will not show as the items will link the supplier that is hidden.

You will need to change the supplier to "Metagenics - Passion 4 Health", this allows the item to show in the inventory.

If you would like to hide a default item that is in the inventory, click the eye icon to the right and this will hide the item. Within the filter bar, you can change the status of inventory from active to inactive, this will allow you to see what items have been hidden and if needed you can click the eye icon to unhide an item and restore it to the inventory.