UI design question

["Dave Foster" <dave foster gmail com>]

Hi,

I'm crossposting to both the usability list and gtk app devel list, i hope
this is ok, as I couldn't really see where my question fit in.  I am
designing a gtk application and I'm trying to follow the HIG, and I wanted
to get some opinions on a "simple" dialog in the application.  Here is a
description (chopped out of an email i sent to a friend earlier):

I've come up with 5 distinct actions this dialog should have.  The actions
are as follows:
- Create a new theme
- Create a new theme based on an existing theme
- Open an existing theme
- Edit current theme
- Open last edited theme

(the last two items will have text inserted at run time to explain what
those theme names are)

I thought the best way to do this was a radio button group, as it would show
all the available actions neatly on one screen.  The problem is, there is
additional information that needs to be taken in depending on what is
selected.  For the top two items (both creates), a theme name must be given
in a text box.  For the create new based on existing and open existing, a
theme needs to be selected from a list of themes.

Because of these additional controls, I don't know how to lay this dialog
out so that the user can see that the listbox and textbox are dependant on
selections in the radio group.

Another idea is to use a drop down, which could be put above the
textbox/listbox, and have those go sensitive/insensitive as appropriate, but
i feel that masks the user from seeing the possibilities of opening/creating
themes.

Yet one more idea is to use a multiple screen approach, with simple buttons
that have nice icons that indiciate which action to take, and have a second
dialog then ask for the required information such as a name or existing
theme, but i feel multiple screens is a bit wizardy and not needed.

Any thoughts?  thanks all.
dave