Sorry typo: The border cells must have their origin in the lower RIGHT corner.
Hi Marianne - can I ask why the origin has to be at the bottom right?
The short answer is "tradition". That way the head is always in the same place on all drawings, no matter how long they become.
So I will hazard a guess here and say that if you create your A3 sheet with origin at bottom left (as A3 will never get longer), it will work properly. I have seen sheets defined in 'reverse'.
That may solve the problem for A3 sheets only, but I'll have to define the long sheets later anyway.
Originally I did try to follow the videos with the delivered files (slightly modified), and I got a similar problem then too. So maybe something else is wrong. In my seed file maybe?