EDIT

      <handlers xmi:id="_mUM1cLKVEeikjKoOnLFm2w" elementId="eu.etaxonomy.taxeditor.editor.descriptiveDataSet.matrix.handler.CreateDefaultTaxonDescriptionHandler" contributionURI="bundleclass://eu.etaxonomy.taxeditor.editor/eu.etaxonomy.taxeditor.editor.descriptiveDataSet.matrix.handler.CreateDefaultTaxonDescriptionHandler" command="_ZHC3oLKVEeikjKoOnLFm2w"/>

      <handlers xmi:id="_t8dAQLKVEeikjKoOnLFm2w" elementId="eu.etaxonomy.taxeditor.editor.descriptiveDataSet.matrix.handler.CreateLiteratureTaxonDescriptionHandler" contributionURI="bundleclass://eu.etaxonomy.taxeditor.editor/eu.etaxonomy.taxeditor.editor.descriptiveDataSet.matrix.handler.CreateLiteratureTaxonDescriptionHandler" command="_fkPkkLKVEeikjKoOnLFm2w"/>

      <menus xsi:type="menu:PopupMenu" xmi:id="__10yYLKREeikjKoOnLFm2w" elementId="eu.etaxonomy.taxeditor.editor.popupmenu.charactermatrix">

        <children xsi:type="menu:HandledMenuItem" xmi:id="_AyHbgLKSEeikjKoOnLFm2w" elementId="eu.etaxonomy.taxeditor.editor.handledmenuitem.createdefaultdescription" label="Create default description" command="_ZHC3oLKVEeikjKoOnLFm2w"/>

        <children xsi:type="menu:HandledMenuItem" xmi:id="_DYlHcLKSEeikjKoOnLFm2w" elementId="eu.etaxonomy.taxeditor.editor.handledmenuitem.createliteraturedescription" label="Create literature description" command="_fkPkkLKVEeikjKoOnLFm2w"/>

      </menus>

    <elements xsi:type="commands:Command" xmi:id="_ZHC3oLKVEeikjKoOnLFm2w" elementId="eu.etaxonomy.taxeditor.editor.charactermatrix.command.createDefaultTaxonDescription" commandName="Create default taxon description"/>

    <elements xsi:type="commands:Command" xmi:id="_fkPkkLKVEeikjKoOnLFm2w" elementId="eu.etaxonomy.taxeditor.editor.charactermatrix.command.createLiteratureTaxonDescription" commandName="Create literature taxon description"/>

import org.eclipse.e4.ui.services.EMenuService;

import org.eclipse.jface.viewers.IStructuredSelection;

import org.eclipse.jface.viewers.StructuredSelection;

import org.eclipse.nebula.widgets.nattable.config.AbstractUiBindingConfiguration;

import org.eclipse.nebula.widgets.nattable.coordinate.Range;

import org.eclipse.nebula.widgets.nattable.ui.binding.UiBindingRegistry;

import org.eclipse.nebula.widgets.nattable.ui.matcher.MouseEventMatcher;

import org.eclipse.nebula.widgets.nattable.ui.menu.PopupMenuAction;

import org.eclipse.nebula.widgets.nattable.ui.menu.PopupMenuBuilder;

import org.eclipse.swt.widgets.Menu;

    @Inject

    private EMenuService menuService;

      //+++CONTEXT MENU+++

        menuService.registerContextMenu(natTable, "eu.etaxonomy.taxeditor.editor.popupmenu.charactermatrix"); //$NON-NLS-1$

        // get the menu registered by EMenuService

        final Menu e4Menu = natTable.getMenu();

        // remove the menu reference from NatTable instance

        natTable.setMenu(null);

        natTable.addConfiguration(

                new AbstractUiBindingConfiguration() {

            @Override

            public void configureUiBindings(

                    UiBindingRegistry uiBindingRegistry) {

                // add e4 menu to NatTable

                new PopupMenuBuilder(natTable, e4Menu)

                    .build();

                // register the UI binding for header, corner and body region

                uiBindingRegistry.registerMouseDownBinding(

                        new MouseEventMatcher(

                                SWT.NONE,

                                null,

                                MouseEventMatcher.RIGHT_BUTTON),

                        new PopupMenuAction(e4Menu));

            }

        });

    public IStructuredSelection getSelection(){

        Set<Range> selectedRowPositions = bodyLayer.getSelectionLayer().getSelectedRowPositions();

        List<Object> selectedObjects = new ArrayList<>();

        for (Range range : selectedRowPositions) {

            for(int i=range.start;i<range.end;i++){

                selectedObjects.add(bodyDataProvider.getRowObject(i));

            }

        }

        return new StructuredSelection(selectedObjects);

    }

import org.eclipse.jface.viewers.IStructuredSelection;

    public IStructuredSelection getSelection(){

        return matrix.getSelection();

    }

    public CharacterMatrix getMatrix() {

        return matrix;

    }

/**

* Copyright (C) 2018 EDIT

* European Distributed Institute of Taxonomy

* http://www.e-taxonomy.eu

*

* The contents of this file are subject to the Mozilla Public License Version 1.1

* See LICENSE.TXT at the top of this package for the full license terms.

*/

package eu.etaxonomy.taxeditor.editor.descriptiveDataSet.matrix.handler;

import eu.etaxonomy.cdm.model.common.MarkerType;

/**

 * @author pplitzner

 * @since Sep 7, 2018

 *

 */

public class CreateDefaultTaxonDescriptionHandler extends CreateTaxonDescriptionHandler{

    @Override

    protected boolean getMarkerFlag() {

        return true;

    }

    @Override

    protected MarkerType getMarkerType() {

        return MarkerType.USE();

    }

}

/**

* Copyright (C) 2018 EDIT

* European Distributed Institute of Taxonomy

* http://www.e-taxonomy.eu

*

* The contents of this file are subject to the Mozilla Public License Version 1.1

* See LICENSE.TXT at the top of this package for the full license terms.

*/

package eu.etaxonomy.taxeditor.editor.descriptiveDataSet.matrix.handler;

import eu.etaxonomy.cdm.model.common.MarkerType;

/**

 * @author pplitzner

 * @since Sep 7, 2018

 *

 */

public class CreateLiteratureTaxonDescriptionHandler extends CreateTaxonDescriptionHandler{

    @Override

    protected boolean getMarkerFlag() {

        return true;

    }

    @Override

    protected MarkerType getMarkerType() {

        return MarkerType.IN_BIBLIOGRAPHY();

    }

}

/**

* Copyright (C) 2018 EDIT

* European Distributed Institute of Taxonomy

* http://www.e-taxonomy.eu

*

* The contents of this file are subject to the Mozilla Public License Version 1.1

* See LICENSE.TXT at the top of this package for the full license terms.

*/

package eu.etaxonomy.taxeditor.editor.descriptiveDataSet.matrix.handler;

import javax.inject.Named;

import org.eclipse.e4.core.di.annotations.CanExecute;

import org.eclipse.e4.core.di.annotations.Execute;

import org.eclipse.e4.ui.di.UISynchronize;

import org.eclipse.e4.ui.model.application.ui.basic.MPart;

import org.eclipse.e4.ui.model.application.ui.menu.MHandledMenuItem;

import org.eclipse.e4.ui.services.IServiceConstants;

import org.eclipse.jface.viewers.IStructuredSelection;

import eu.etaxonomy.cdm.api.service.IDescriptiveDataSetService;

import eu.etaxonomy.cdm.api.service.dto.TaxonRowWrapperDTO;

import eu.etaxonomy.cdm.model.common.MarkerType;

import eu.etaxonomy.cdm.model.description.DescriptiveDataSet;

import eu.etaxonomy.cdm.model.taxon.TaxonNode;

import eu.etaxonomy.taxeditor.editor.descriptiveDataSet.matrix.CharacterMatrixPart;

import eu.etaxonomy.taxeditor.store.CdmStore;

/**

 * @author pplitzner

 * @since Sep 7, 2018

 *

 */

public abstract class CreateTaxonDescriptionHandler {

    @Execute

    public void execute(@Named(IServiceConstants.ACTIVE_PART)MPart activePart, UISynchronize sync) {

        CharacterMatrixPart matrixPart = (CharacterMatrixPart) activePart.getObject();

        DescriptiveDataSet descriptiveDataSet = matrixPart.getDescriptiveDataSet();

        TaxonNode node = (TaxonNode) matrixPart.getSelection().getFirstElement();

        TaxonRowWrapperDTO taxonRowWrapperDTO = CdmStore.getService(IDescriptiveDataSetService.class)

                .createTaxonDescription(descriptiveDataSet.getUuid(), node.getUuid(), getMarkerType(), getMarkerFlag());

        matrixPart.getMatrix().getDescriptions().add(taxonRowWrapperDTO);

    }

    protected abstract boolean getMarkerFlag();

    protected abstract MarkerType getMarkerType();

    @CanExecute

    public boolean canExecute(@Named(IServiceConstants.ACTIVE_PART)MPart activePart,

            MHandledMenuItem menuItem){

        boolean canExecute = false;

        IStructuredSelection selection = ((CharacterMatrixPart)activePart.getObject()).getSelection();

        canExecute = selection.size()==1

                && selection.getFirstElement() instanceof TaxonNode;

        menuItem.setVisible(canExecute);

        return canExecute;

    }

}