gtk:widget-path-append-with-siblings (path siblings index)

path -- a gtk:widget-path instance
siblings -- a gtk:widget-path instance describing a list of siblings, this path may not contain any siblings itself and it must not be modified afterwards
index -- an unsigned integer with the index into siblings for where the added element is positioned

An integer with the position where the element was inserted.

Appends a widget type with all its siblings to the widget hierarchy represented by path. Using this function instead of the gtk:widget-path-append-type function will allow the CSS theming to use sibling matches in selectors and apply :nth-child() pseudo classes. In turn, it requires a lot more care in widget implementations as widgets need to make sure to call the gtk:widget-reset-style function on all involved widgets when the siblings path changes.