Line-menu: how to vertically move image in [manual] mode?

[jdelange]

Trying to reposition the image in vertical position. I can enter the line menu and select the vertical alignment.

I can select between [auto] and [manual] vertical position and the screen does shift up or down one big step by selecting either option, but when in [manual] mode, I cannot seem to manually control the position, which is what you would expect to be possible in manual mode?

Pressing short on the buttons toggles between [auto] / [manual], pressing long on the buttons, moves me to the next or previous menu item.

So when in [manual] vertical adjustment mode: how do I manually adjust the screen position up or down?

Edit: solved: when selecting manual, a long press moves the menu selection to the right where there is a number that can be adjusted with short presses. That changes the offset.

Setting it to 0 was the best I could do, but it did not recover my lost scan lines at the top of the screen.