Hi,
Oh! joy. I can't work out how to answer to replies, or even read them more than once so I have to reply to my own question.
Anyway to clarify.
When I boot the machine the dock appears at the bottom center when I put the mouse down there. That is my custom choice, and the desired behavior. I much prefer it to the Windows Taskbar.
When the screen saver cuts in, and I reactivate the screen, all is still well.
When the machine goes to sleep, and I sign back in, the dock is parked in the top left corner. It does not activate when I run the mouse over it . The icons are on top of each other, and the bar is up there as well. In other words the reference coordinates of the graphics have all been set to zero, and/or the dock has not been made invisible. The custom behavior of the dock is not persisted through sleep, and does not reset until I run the mouse over the bottom of the screen, which then erases the spurious dock.
I originally thought this was a feature to protect it against getting lost when, I don't know, multiple screens with different resolutions are used etc. However, it's getting to be very irritating. It would be nice to move the parking position, to say the bottom right, or just get rid of it..
Paul P.