@Override
    public boolean isEditing(final Context context, final Element parent, final TickBoxState value) {
        // A checkbox is never in "edit mode". There is no intermediate state
        // between checked and unchecked.
        return false;
    }
Construct a new {@link CheckboxCell} that optionally controls selection.

@param dependsOnSelection true if the cell depends on the selection state
@param handlesSelection   true if the cell modifies the selection state
stroom-core-client-widget/src/main/java/stroom/cell/tickbox/client/TickBoxCell.java