the #GtkCellAreaContext in context with the current row data
the #GtkWidget that @area is rendering on
the size and location of @area relative to @widget’s allocation
the #GtkCellRendererState flags for @area for this row of data.
if %TRUE then only cell renderers that are %GTK_CELL_RENDERER_MODE_EDITABLE will be activated.
Whether @area was successfully activated.
3.0
Activates @area, usually by activating the currently focused cell, however some subclasses which embed widgets in the area can also activate a widget if it currently has the focus.