Fix of 4530: TextInput of PreferenceBrowser behave strangely

> Hi,
>
> I committed a fix to The Inbox of http://bugs.squeak.org/view.php?id=4530
> TextInput of PreferenceBrowser behave strangely.
>
>    The root of the problem was that on each keystroke the
> PluggableTextMorph updated the PreferenceBrowser, which in turn
> updated the PluggableTextMorph, what messed up its selection.
>    This solution gives a getTextSelector to the PluggableTextMorph
> which is never triggered.
>    Another solution could be to drop the auto updating behaviour.
>
> Balázs
>
>