Widgets can be a pain mostly depending on where you are adding them.
I highly recommend using player controller events because if you add them in say a item blue print hen they will end up belonging to the item so the item is destroyed the reference can be lost and it is then stuck on screen.
But if your event is called in controller to add the widget you can set the player admits owner and hold the reference so even if the player dies etc they still have the reference because your not removing the controller ever.