bug#2996: 23.0.92; Scrolling narrows region

[Chong Yidong <cyd@stupidchicken.com>]

> 1. emacs -Q
> 2. C-x C-f file 
>    file should contain more than a screenfull of text.
> 3. Right-click somewhere in the window to produce an active region. If
>    you didn't move point before this, the region starts at the very top
>    of the buffer.
> 4. Right-click somewhere further down to see, that the region is
>    resized. 
> 5. Scroll down using the mousewheel, until the point moves. This
>    happens, when point touches the upper window border.
>
>    The mark is now moved from the very top of the buffer, to the first
>    visible line.

When point moves due to scrolling, the mark is deactivated---at least,
that's what I observe.  This does not move the mark; it remains at the
same position as before, just deactivated.  You can verify this with C-x
C-x.

So I don't see any bug here.