Returns the current header of the @row. This can be used in a #GtkListBoxUpdateHeaderFunc to see if there is a header set already, and if so to update the state of it.
Return: the current header, or %NULL if none
3.10
See Implementation
Returns the current header of the @row. This can be used in a #GtkListBoxUpdateHeaderFunc to see if there is a header set already, and if so to update the state of it.
Return: the current header, or %NULL if none