bug#45839: 28.0.50; Isearch and transient mode wierd behaviour in info-mode!

[Drew Adams]

> Please see in the function 'Info-search' that it intentionally
> deactivates the active region during the search by calling:
> 
>   (deactivate-mark)
> 
> This is because when the search arrives in another Info node,
> then region highlighting breaks - the region's beginning stays
> in the previous node, while the region's end moves to the next node.
> To avoid such situation, it deactivates the active region.

FWIW, Info+ doesn't have this problem.  It deactivates
the mark only when search moves to another node.
___

If library Isearch+ is also loaded then when search
stays in the same node the mark is deactivated if
option `isearchp-deactivate-region-flag' is non-nil
(the default).  You can toggle this anytime during
Isearch with `M-= C-SPC'.

So you control the behavior for search within a node,
and deactivation happens when search moves to another
node.