The SPLITTER attribute forces the container to use a splitter widget between each child element.
SPLITTER
This attribute indicates that the container (typically, a VBOX or HBOX) must have a splitter between each child element held by the container. If a container is defined with a splitter and if the children are stretchable (like TABLE or TEXTEDIT), users can resize the child elements inside the container.
VBOX ( SPLITTER )