view builder

Hi,

Not all the view files have a view builder.
For example, the product / show_block_custom_item of your screenshot doesn't have a view builder because it only has one element in it.
Look instead at product / show_default and you'll see something like this:
i.imgur.com/IIxxzZ9.png

Hi,

It's possible that the save doesn't work if you have a security system in place which prevents the code of the view coming from the browser to be retrieved by the server.
Still, when you move the block with the view builder, the code in the code editor below will be updated. So before saving, copy the whole code and paste it in a new file on your local computer. Then, you can upload it via FTP or the file manager of your hosting to templates/YOUR_TEMPLATE/html/com_hikashop/product/show_default.php and the system will find the override as if you had done it via the save button.