@item @var{text-pos}
For clicks on a marginal area or on a fringe, this is the buffer
position of the first visible character in the corresponding line in
-the window. For other events, it is the current buffer position in
-the window.
+the window. For clicks on the mode line or the header line, this is
+@code{nil}. For other events, it is the buffer position closest to
+the click.
@item @var{col}, @var{row}
These are the actual column and row coordinate numbers of the glyph