[UMG] Drag and Drop Inventory?

Ok, so i moved the ButtonDown and DragDetect into the ItemWidget. But it is not receiving ANY ButtonDown info. It is the top most (as you can see in the picture above) and all components ,even the root, is set to be visible.
As you suggested in the post you linked, the Roots of both the Draggable and the Droppable Widgets are set to Visible. Is there anything else i need to consider?

Thanks for your help so far.

EDIT: To maybe help you understanding what i may do wrong:

InventoryWidget with Grid, all set to Hit Test:

InventorySlot with Background Image (white), all set to visible:

ItemWidget, with Image that is bind to the Item Ref, all set to visible:

OnDrop in InventorySlot calling my ServerFunction:

OnMouseButtonDown in the ItemWidget:

OnDragDetected in the ItemWidget: