In the order in "Waiting for Payment" status there is a button "Process Order if Payments are received" or "Payment Received", clicking the button seems not to affect anything. What is the purpose of the button?
In the current implementation all Order Flow transitions are represented with corresponding buttons on order screen. "Process Order if payments are received" button represents the following transition from the default order flow:
WP On Event -> WP Waiting for Payment/PD Paid or Payment is postponed
The transition is on event, which means that as soon as payment received, an order will go to PD status automatically, there is no need to click the buttons. If required, Process Order if payments are received can be hidden by adding underscore sign in the beginning of the transition action: