Our initial releases of the WP Paintbrush beta have included a feature which allows for changing designs only from within the front-end editor. The new version of WP Paintbrush released earlier today has removed this functionality and replaced it with a much better system involving child themes. Now instead of changing designs from the front-end editor, you can use the regular WordPress theme page to select a child theme of WP Paintbrush. Head over to the downloads page to check out the new version.
We only have one child theme available at the moment, but we will be adding more over time. Check out the WP Paintbrush 2011 child theme to try the first one out.

Regular themes admin page in WordPress, demonstrating the new child theme functionality for WP Paintbrush.
Re-editing old designs
The new child themes can be edited individually. When you change to another child theme, edit that, then go back to the original child theme, the design you were working on will still be available. Previously changing back to the original design you had been working on would wipe all of your changes. Of course it is possible that you may wish to reset the theme back to the original design, you can do this by using the “Reset” feature found under the “Appearance” menu in your WordPress admin panel. This allows you to take the individual child theme back to it’s original design.
Exporting child themes
We will have an export tool for creating your own WP Paintbrush child themes available within the next week.