When using parent_slug => options-general.php to get the options page to show up under the standard Settings menu, the library will cause the "Settings Saved" message to be shown twice when saving the form.

If using parent_slug => tools.php it works as expected and only shows the "Settings saved" message once.
When using parent_slug => options-general.php to get the options page to show up under the standard Settings menu, the library will cause the "Settings Saved" message to be shown twice when saving the form.
If using parent_slug => tools.php it works as expected and only shows the "Settings saved" message once.