Check this out. In the screenshot you can see me doing edits and analysis on the userinterface of a running Evolution instance. Like getting and setting the properties of the userinterface-widgets. For illustration I’ve set the second button on the toolbar invisible. You can find more about g-inspector here.
Related information: For people who need accesibility-aid, you can checkout at-poke. It allows you to poke-around in widgets that have accesibility-support.