New expander style

[Tristan Van Berkom <tvb gnome org>]

Hi all,
    This is a call for comments on a proposed alternative look'n'feel
to the GtkExpander, this bug: http://bugzilla.gnome.org/show_bug.cgi?id=345778
contains a screenshot of the glade3 palette that uses this functionality
and a patch that implements it as a style property.

So my questions to the gtk devs/comminity are:

  o Do we want to have such an expander easily available in gtk+ ?
    (would you use it ? is it such a corner case that its not worth adding
    a few lines of code for ?)

  o What would be the implementation of preference ?
    - It was argued that any style properties should be targetted at
      theme writers - and this property shouldnt be theme specific.
      [ personally I think its fine to have style proprties that are not controlled
        by the theme - but that might be beside the point ]
    - Maybe a normal GObject property would be more suitable; other examples of
      properties in gtk+ that effect the look'n'feel can be found, "draw-as-radio"
      on GtkToggleMenuItem is an example.
    - A subclass of GtkExpander that looks'n'feels different, the
      expander->priv->prelight and expander->priv->expander_style members would have
      to be somhow exported for the subclass to be able to properly override
      the ->expose method (and do something usefull).

My thoughts are:
  o Currently I have a copy/paste of gtkexpander.c in
    $(gnomecvs)/glade3/src/glade-palette-expander.c that is essentially few lines
    different from gtkexpander.c (all the namespace crap aside)
  o It shouldn't be /that/ hard to achieve this basic effect, since subclassing
    the expander isnt possible due to expander->priv->evil, we could at least
    get it configurable in the expander proper, unless ofcourse we're the only
    ones that find this to be a usefull expander functionality.

Thanks for all of your attention in this matter :)

Cheers,
                      -Tristan