Overflow overflow

Whether overflowing children should be clipped. See Overflow.

Some children in a stack might overflow its box. When this flag is set to Overflow.clipped, children cannot paint outside of the stack's box.

Source 

Overflow get overflow => _overflow;
void overflow=(Overflow value)

Source 

set overflow (Overflow value) {
  assert(value != null);
  if (_overflow != value) {
    _overflow = value;
    markNeedsPaint();
  }
}