[noelcm]

Thanks, mate. Now we're getting somewhere.
When I click on "custom position" the yellow "Subtitle Sample" appears at the bottom of the screen superimposed on the primary subtitle (in the middle of the bottom).
When I move the mouse pointer to it nothing happens - until I move the pointer up.
Halfway up the screen the sub begins to move.
When the mouse pointer reaches the top of the screen the sub is in the dead centre of the screen - and will go no further.
If the sub attached to the pointer as you describe it would be great - but it don't.
What sayest you??

Would you correct me if I am wrong please?
When clicking on "custom position" for the Secondary subtitle, the Subtitle Sample should appear at the very TOP, not bottom, of the screen.
(The primary subtitle, upon clicking custom position, appears, correctly, at the bottom of the screen)
This should be a simple programming fix, but I would not know where to start!