EDIT

        Composite composite_4 = new Composite(composite_3, SWT.NONE);

        formToolkit.adapt(composite_4);

        formToolkit.paintBordersFor(composite_4);

        GridLayout gl_composite_4 = new GridLayout(1, false);

        gl_composite_4.marginWidth = 0;

        composite_4.setLayout(gl_composite_4);

        Button btnAddCharacter = new Button(composite_4, SWT.NONE);

        Button btnAddRatioTo = new Button(composite_4, SWT.NONE);

        btnAddRatioTo.setText("ratio to"); //$NON-NLS-1$

        btnAddRatioTo.setSize(btnAddCharacter.getSize());

        formToolkit.adapt(btnAddRatioTo, true, true);

        btnAddRatioTo.addSelectionListener(new SelectionAdapter() {

            @Override

            public void widgetSelected(SelectionEvent e) {

                if(!isVocabularySet()){

                    return;

                }

                if (confirmSaveDirty()){

                    return;

                }

                ISelection structureTreeSelection = structureViewer.getSelection();

                ISelection characterSelection = characterTreeEditorComposite.getViewer().getSelection();

                if(structureTreeSelection==null || characterSelection ==null){

                    MessagingUtils.warningDialog(Messages.CharacterEditor_CANNOT_PERFORM_TITLE, CharacterEditor.this,

                            Messages.CharacterEditor_CANNOT_PERFORM_MESSAGE);

                    return;

                }

                CharacterNodeDto character = (CharacterNodeDto)((TreeSelection)characterSelection).getFirstElement();

                TermNode ratioToNode = (TermNode)((TreeSelection)structureTreeSelection).getFirstElement();

                if (character == null){

                    return;

                }

                TermDto termDto = character.getTerm();

                if (termDto instanceof CharacterDto){

                    CharacterDto dto = (CharacterDto)termDto;

                    dto.setRatioTo(TermNodeDto.fromNode(ratioToNode, null));

                }

//                Collection<Character> characters = createCharacters((TreeSelection)structureTreeSelection, (TreeSelection)propertyTreeSelection);

                TermNodeDto parent = characterTreeEditorComposite.getFeatureTree().getRoot();

//                for (Character character : characters) {

//                    //add new Character to feature tree

//                    CharacterNodeDto nodeDto = new CharacterNodeDto(CharacterDto.fromCharacter(character), parent, 0, parent.getTree(), null, null, null);

//                    nodesToSave.put(character, nodeDto);

//                    setDirty();

//                    //                    result = CdmStore.getService(IFeatureNodeService.class).createChildFeatureNode(parent.getUuid(), character, vocabulary.getUuid());

//

//                }

                setDirty();

                nodesToUpdate.add(character);

                refresh();

                characterTreeEditorComposite.getViewer().setSelection(new StructuredSelection(character));

            }

        });

    private Label labelText_ratioTo;

    private Text text_ratioTo;

        if (labelText_ratioTo != null){

            labelText_ratioTo.dispose();

        }

        labelText_ratioTo =  new Label(formElement.getLayoutComposite(), SWT.NONE);

        labelText_ratioTo.setText("Ratio to");

        if (text_ratioTo != null){

            text_ratioTo.dispose();

        }

        text_ratioTo = new Text(formElement.getLayoutComposite(), SWT.WRAP);

        text_ratioTo.setEditable(false);

        if (entity.getRatioTo() != null){

            text_ratioTo.setText(entity.getRatioTo().getPath());

        }

        text_ratioTo.setLayoutData(LayoutConstants.FILL());

        text_ratioTo.setForeground(ColorResources.getColor(Resources.BLACK));