bug#39424: auto-scrolling

[Konrad Podczeck]

I observe the following discrepancy between (a) mouse-drag-region and (b) 
mouse-drag-region-rectangle.

Concerning (a), as soon as one comes with the mouse below the mode-line of the 
frame, so that auto-scrolling becomes effective, the cursor jumps to the 
beginning of the line below the region and that line appears as non-selected 
during further scrolling.

As for (b), as usual with other text editors, if one comes with the mouse below 
the mode-line of the frame, the cursor stays at the beginning or end of the 
region, and there is no line which appears non-selected.

I could neither find any explanation for this discrepancy in the manuals, nor a 
customization option which, for (a), gives the same behavior as in case of (b).

Konrad