The Rainmeter documentation tells us
However, I notice that this is only true if @N is specified on WindowX (then the specified screen N is also used for WindowY and the skin is correctly placed on the second, third, ... display). The other way around it's not the case (e.g. if WindowX=123 and WindowY=0@2 the skin is still drawn on screen #1).The screen selection will apply to both WindowX and WindowY if the value is set on only one of them.
Is it possible Rainmeter first processes the value WindowX from the Rainmeter.ini and only afterwards WindowY's value (regardless of whether within a section the value WindowY is perhaps even 1 or more lines further up than WindowX)?
PS. I searched the Rainmeter history, but since implementation of !SetWindowPosition there was nothing changed or fixed.. but it should be indepentend from this bang anyway, I guess...