bug#9609: Excessive transient region highlighting with highlight-nonselected-windows

[Juri Linkov]

>>> But the region's overlay _is_ specific to the window where it is set.
>>> Or are you saying it isn't the region that is highlighted in the other
>>> window?
>>
>> The region is activated in both windows of the same buffer.
>> I thought the problem is here.
>
> What is the region in a non-selected window when point of that window's
> buffer and point of that window differ?

After setting the mark in the selected window,
the region is activated in the selected window between the mark and current 
point,
and also the region is activated in the non-selected window
between the same mark and window-point of the non-selected window.