Adds @sibling to @renderer’s focusable area, focus will be drawn around @renderer and all of its siblings if @renderer can focus for a given row.
Events handled by focus siblings can also activate the given focusable @renderer.
the #GtkCellRenderer expected to have focus
the #GtkCellRenderer to add to @renderer’s focus area
See Implementation
Adds @sibling to @renderer’s focusable area, focus will be drawn around @renderer and all of its siblings if @renderer can focus for a given row.
Events handled by focus siblings can also activate the given focusable @renderer.