Text-editing widget

Hi usability team,

I'm Stéphane Maniaci, the summer of code student working on the
presentation software, Ease [0]. I wanted to ask you designers about
how Ease generally feel, but this is definitely not a good question
since lot of changes are happening and the UI is not stable yet, at
all.

However, I'm currently working on a text-editing widget, that is a
widget which preview the text you're going to insert in your document,
but also shows you some cool options like a shadow, outline or inset,
plus all the sub-options of those (width, blur of the shadow,
etc...). Basically, that means a ClutterStage on the left (a canvas),
and the whole make-your-text-pretty configuration thing on the left.

I came up with a _very_ basic mockup of this widget [1] but :
1. I don't know if it's good ;
2. I don't really know how to implement it (GtkBox, GtkTable,
GtkExpander?).

So if you designers have a little time to spare, I would appreciate
your ideas and feedback about that. If that is of any help, you can
look at the Photoshop text dialog [2].

Thanks!

Stéphane.

[0] : http://live.gnome.org
[1] : http://img203.imageshack.us/img203/348/textwidget.png
[2] : http://www.photoshopessentials.com/images/type/effects/gold/layer-style-dialog-box.jpg