Thanks for the further response.(I knew I was right to go for this program rather than MusicReader because the support just looked so much better!)
I will send you by email two of my scanned in PDFs, one taking up half a page of A4 and the other a full page.
With the half page of music, all that is required is to be able to fix the zoom at the level at which everything is on the screen. There is no part of the page hidden. It is usable in this way now, when one has to select it each time when moving the song into full screen mode. But ideally the zoom level should be savable with the song file.
For a full page the problem with fixing such a zoom level is, as you say, that some part of the page, possibly half or more, will be off the screen. But that was the reason for my other suggestion. If the screen scrolling function were not confined to the Windows on screen slider, but were also allocated as in most other Windows programs, to the up and down arrows and the mouse scroll wheel - which is the way it works in this message in fact when the message exceeds the pane size - one would have a ready means of pulling up the music on the rest of the page. And since the arrows are keystrokes, there would be the added benefit of being able to ascribe them to a suitable foot pedal. The zoom function would no longer be available on the mouse scroll wheel, but that would be of less consequence because the zoom can be set with mouse clicks before starting to play, and ideally would once chosen be saved with the song file. (In my case the change would also avoid my zooming by mistake when my reflexes automatically seek to scroll with the wheel).
I appreciate your taking an interest in the particular problem I am facing. I suppose in a perfect world, given that other users may have different requirements, these various preferences would be selectable from a pull down menu attached to a ‘settings’ button. But I guess I am pushing my luck now! Thanks for listening.