Sorry for the inconvenience, We had checked our theme-pure and simple on latest WP4.5 and its working fine here. So make sure you are using latest version
of pure simple.
If still you are facing the customization issue, please send us your wp login details at [email protected].
Note: Please take a backup of your site before preceding, so you can take a action when disaster strikes. And also please try by deactivating all plugins, so we can be sure that this issue is not the plugin conflict.