The attached test script produces a blank plot, with
faint grey gridlines. However, the left-most vertical
gridline is drawn over the x1 axis, and both x1 and y1
axes lose their tick markings beneath the gridlines. I
think the gridlines should be drawn at the back, behind
all of the axes.
Therefore, I think you need to draw all of the
gridlines from all of the axes first, and then draw all
of the axes and tick marks over the top?
test script
See changeset 3266.