public virtual signal void add (Widget widget)
widget to this.
Typically used for simple containers such as Window, Frame, or Button; for more complicated layout containers such as Box or Grid, this function will pick default packing parameters that may not be correct. So consider functions such as pack_start and attach as an alternative to add in those cases. A widget may be added to only one container at a time; you can’t place the same widget inside two different containers.
a widget to be placed inside this