Not really a bug; more of an inconsistency….I propose changing these items to make the UI easier to understand for beginning users….
Firstly, the “BOARDS” label at the top of the Boards column is lower and smaller than the “DOCUMENT” label at the top of the documents.
Second, if these two columns (Boards and Documents) have ‘headers’ like they do now, shouldn’t all columns have a header? For example, every pane should have a header of “List”, “Outline”, “Archived”, “Calendar: Week”, “Moved” as its top row (again, in vertical alignment with the “Boards” and “Documents” headers. This way, every pane/column would have a label indicating what it is representing. Icons for this type of thing can get a bit cumbersome, as they have to be ‘translated’ in the user’s mind before it is obvious what they represent.