In the Full and Simple Editor, by default, the editor shows all the custom fields you have created. So, if you have a very large number of custom fields, all of them (four in the screenshot) will be displayed as shown below.
However, if you have hundreds of custom fields, and you just wish to enter details just for a few, you can simply select a previously created group and only custom fields within that group will be displayed.
For example, the Group named "Supplier Details" has only 3 custom fields out of the 4 shown above. When this group is selected, the editor only shows the 3 custom fields that are in that group as shown below.
Similarly, when the group named "Finishing" was selected, only 1 custom field was displayed in the editor rather than all 4.
