cannot set domain theme

It works for me. Question:

When you go to assign a theme for alpha.example.com, does the URL change to:

alpha.example.com/admin/build/domain/theme/1

It should. In some cases we have to force you to be on the domain you wish to edit.

The fix is related to http://drupal.org/node/186153. So if you aren't being taken to
alpha.example.com/admin/build/domain/theme/1, then there is another bug.

I also assume that "when saving" means "after saving".

That aside, does the theme switch work on the home page(s)?

Strange. Try this:

Open domain_theme_form.inc. Edit this function:

function domain_theme_submit($form_id, $form_values) {
  // ADD THESE LINES
  watchdog('domain', 'Theme settings form invoked');
  drupal_set_message('Theme set');

  $theme = $form_values['theme_default'];
  $id = $form_values['domain_id'];
  $settings = NULL; // This is a placeholder for advanced functions.
  $check = domain_theme_lookup($id);
  if ($check == -1) {
    db_query("INSERT INTO {domain_theme} VALUES (%d, '%s', %b)", $id, $theme, $settings);
  }
  else {
    db_query("UPDATE {domain_theme} SET theme = '%s', settings = %b WHERE domain_id = %d", $theme, $settings, $id);
  }
} 

It sounds as though hook_form_alter() isn't firing correctly -- if it is, then this watchdog message should be logged. Do you have any other theme-based modules installed? (e.g. Taxonomy Theme)

See http://therickards.com/api/file/domain_theme/domain_theme_form.inc/Domain for the documentation.

There was a bug in domain_theme_lookup(). See attached patch.

Committed to HEAD. Thanks.