advanced_forum_theme_registry_alter clears other modules changes

I have a few other modules that use hook_theme_registry_alter to make changes to theme paths, but it all stops working when advanced_forum is installed.

Looking at the code from line 317 in advanced_forum.module, this loop seems to be causing the problem and seems to get very confused with the existing path.

      // If there was a path in there, store it.
      $existing_path = array_shift($theme_registry[$template]['theme paths']);

      // Add paths for our style and ancestors before the existing path, if any.
      foreach ($lineage AS $style => $style_path) {
        array_unshift($theme_registry[$template]['theme paths'], $existing_path, $style_path);
        $existing_path = array_shift($theme_registry[$template]['theme paths']);
      }

It removes the first existing path and then for each iteration it adds it and then removes it once again, leaving it off at the end and I can't see why.

Patch to follow....