Let users access the source code of macros easier

It's very difficult for non-IT users to access the source code of macros. It would be easier if instead of switching to the source tab and looking for the code of a certain macro there'd be a field in the WYSIWYG interface of that macro.

For example for the Box Macro there'd be a field like this when you double click on it:

Source Code
The source code of the macro

{{box title="Test" width="40%"}}
This is a test
{{/box}}

It would be nice if the field is editable also.