There are 3 ways to add content to a heading shown on the following pages.
Once you have added content it always appears with additional information above the actual text. This is to make it easy to identify the paragraph from the library and to allow you to edit it directly from here (the original in the library is what you are changing), move it up or down and if it is not required here, you may also unlink it.
This is also where you define if the paragraph is editable if this option is unchecked the paragraph cannot be edited during tender preparation.
Note: A non editable heading/paragraph will have no icon in the document tree.
