Hi @jamiek47,
Thanks for the info, the issue is definitely theme related.
I have installed it on my site and could see the issue happening.
I noticed that theme is outdated as it hasn’t been updated for over two years and the code used for sidebar doesn’t follow WP development rules so Custom Sidebars can’t do it’s job.
What happens with this theme is that it if you don’t add any widgets in sidebar it will instead load predefined widgets, Archives and Meta.
So when you enable that sidebar to be replaced it reads it as empty and instead of letting Custom Sidebars to load its widgets it shows the default one.
I was able to get it working in the end by editing theme functions.php file and defining widget ID like this:
register_sidebar(array(
'name' => 'Right Sidebar',
'id' => 'right-sidebar',
'before_widget' => '<div class="widget">',
'after_widget' => '</div>',
'before_title' => '<h3>',
'after_title' => '</h3>',
));
Where ‘id’ => ‘right-sidebar’ is the part that I added.
After that I had to add one widget to “Right Sidebar”, enable for it to be replace and select it in single post again as well.
Also, widget styling was wrong so I had to edit my custom sidebar and add proper widget and title holders like this:
https://screencast.com/t/rZ6iVxxbKHR2
So after all that it started working fine but I would strongly suggest switching to newer theme that’s still supported by its developers.
Cheers,
Predrag