When used in a TreeTableColumn, the CheckBoxCell is rendered with a CheckBox centered in the column.
ObservableValue<Boolean> contained within each cell in the
column will be bound bidirectionally. This means that the CheckBox in
the cell will set/unset this property based on user interactions, and the
CheckBox will reflect the state of the
if it changes externally).
Callback that will return a
TreeTableCell that is
able to work on the type of element contained within the TreeTableColumn.