(This is related to bug 152555 and bug 152537.) There is confusion about how to style the numbers of a line numbering, see the discussions in the mentioned bugs. This topic is not explained in the help. Relevant sections in the help are "Adding Line Numbers" and "Tools - Line Numbering". I suggest to add an information like sketched below to the help: The numbers of the line numbering are styled by the character style “Line Numbering” in the default settings. This style is initially empty. Since the numbers are not embedded in a paragraph, they therefore use the global document settings specified in the Tools - Options dialog box. To style the numbers in a specific way (set font, character size or color for example) specify the desired style aspects in the character style “Line Numbering”. Settings actually included in a style are listed in section “Contains” in the “Organizer” tab of a style dialog. To use a different style than “Line Numbering”, select it from the drop-down list “Character style” in the Tools - Line Numbering dialog.
Sounds good to me, thanks Regina.