Drawn grid not appearing in Print Preview yet ok in previous files

I am using Layout, (love it)
I have done 18 different ones so far, each time I make a copy of the previous Rhino .3dm and rename it e.g Layout 6, then after I am done and saved, and pdf made, I do a ‘save as’, and name it layout 7, alter all the objects to suit, print as a pdf with grid again, and so on, so it uses the same drawn grid each time which appears grey in the pdf print.

Until now that is, and this file, same grid, (as it is a copy of a previous file), refuses to show the drawn grid in the File>print dialog print preview window.

What can I look for to find out why. ? (grid layer is ‘on’ by the way !)

I have done a screen capture compare of a previous file and all settings in print dialog are same.

I give the grid a very visible colour, still doesnt show.