[Cin] Clarification (bug tracker and mailing-list)

Hi. I saw that the Bug Tracker also includes requests for new features, not just Bug. For example, new features for masks. If I want to request a new feature should I use the bug tracker or mailing-list? Another question: If I want to add other features to a bug already written by others (e.g. more options to the mask bug), can I add it to the existing bug (with a note) or do I have to create a new one?