Explicitly sets the currently focused cell to @renderer.
This is generally called by implementations of
#GtkCellAreaClass.focus() or #GtkCellAreaClass.event(),
however it can also be used to implement functions such
as gtk_tree_view_set_cursor_on_cell().
Explicitly sets the currently focused cell to @renderer.
This is generally called by implementations of #GtkCellAreaClass.focus() or #GtkCellAreaClass.event(), however it can also be used to implement functions such as gtk_tree_view_set_cursor_on_cell().