bug#2996: 23.0.92; Scrolling narrows region

[martin rudalics]

> Here's the recipe:
>
> 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.

I suppose it's due to that change:

2008-04-08  Chong Yidong  <cyd@stupidchicken.com>

        * mwheel.el (mwheel-scroll): Deactivate any temporarily active
        region if point moves.

Could you try to

(1) check your scenario with `transient-mark-mode' disabled, and

(2) check your scenario with Chong's change reverted?

martin