diff --git a/src/beastfx/app/beauti/MRCAPriorProvider.java b/src/beastfx/app/beauti/MRCAPriorProvider.java
index 882debb..e08534e 100644
--- a/src/beastfx/app/beauti/MRCAPriorProvider.java
+++ b/src/beastfx/app/beauti/MRCAPriorProvider.java
@@ -2,12 +2,14 @@
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Set;
 
 import beastfx.app.util.Alert;
 
 import beastfx.app.inputeditor.BEASTObjectPanel;
 import beastfx.app.inputeditor.BeautiDoc;
 import beastfx.app.inputeditor.TaxonSetDialog;
+import beast.base.evolution.alignment.Taxon;
 import beast.base.evolution.alignment.TaxonSet;
 import beast.base.evolution.tree.MRCAPrior;
 import beast.base.evolution.tree.Tree;
@@ -53,7 +55,8 @@ public List<Distribution> createDistribution(BeautiDoc doc) {
             prior.treeInput.setValue(trees.get(treeIndex), prior);
             TaxonSet taxonSet = new TaxonSet();
 
-            TaxonSetDialog dlg = new TaxonSetDialog(taxonSet, PriorListInputEditor.getTaxonCandidates(prior, doc), doc);
+            Set<Taxon> candidates = PriorListInputEditor.getTaxonCandidates(prior, doc);
+            TaxonSetDialog dlg = new TaxonSetDialog(taxonSet, candidates, doc);
             if (!dlg.showDialog() || dlg.taxonSet.getID() == null || dlg.taxonSet.getID().trim().equals("")) {
                 return null;
             }
diff --git a/src/beastfx/app/inputeditor/TaxonSetDialog.java b/src/beastfx/app/inputeditor/TaxonSetDialog.java
index 72637fc..4e43c1d 100644
--- a/src/beastfx/app/inputeditor/TaxonSetDialog.java
+++ b/src/beastfx/app/inputeditor/TaxonSetDialog.java
@@ -14,6 +14,7 @@
 import javafx.scene.control.DialogPane;
 
 import javafx.scene.control.Label;
+import javafx.scene.control.ListCell;
 import javafx.scene.control.ListView;
 import javafx.scene.control.SelectionMode;
 import beastfx.app.beauti.ThemeProvider;
@@ -24,6 +25,7 @@
 import javafx.scene.layout.HBox;
 import javafx.scene.layout.Pane;
 import javafx.scene.layout.VBox;
+import javafx.util.Callback;
 
 import javax.swing.UIManager;
 
@@ -165,12 +167,44 @@ Pane createTaxonSelector() {
         listOfTaxonCandidates.setId("listOfTaxonCandidates");
         listOfTaxonCandidates.setMinSize(200,300);
         listOfTaxonCandidates.setPrefSize(200,300);
+        listOfTaxonCandidates.setCellFactory(new Callback<ListView<Taxon>, ListCell<Taxon>>() {
+			@Override
+			public ListCell<Taxon> call(ListView<Taxon> param) {
+				return new ListCell<Taxon>() {
+					@Override
+					public void updateItem(Taxon taxon, boolean empty) {
+						super.updateItem(taxon, empty);
+		                if (empty || taxon == null) {
+		                    setText(null);
+		                } else {
+		                    setText(taxon.getID());
+		                }
+					}
+				};
+			}
+		});
 
         listOfTaxonSet = new ListView<>();
         listOfTaxonSet.getSelectionModel().setSelectionMode(SelectionMode.MULTIPLE);
         listOfTaxonSet.setId("listOfTaxonSet");
         listOfTaxonSet.setMinSize(200,300);
         listOfTaxonSet.setPrefSize(200,300);
+        listOfTaxonSet.setCellFactory(new Callback<ListView<Taxon>, ListCell<Taxon>>() {
+			@Override
+			public ListCell<Taxon> call(ListView<Taxon> param) {
+				return new ListCell<Taxon>() {
+					@Override
+					public void updateItem(Taxon taxon, boolean empty) {
+						super.updateItem(taxon, empty);
+		                if (empty || taxon == null) {
+		                    setText(null);
+		                } else {
+		                    setText(taxon.getID());
+		                }
+					}
+				};
+			}
+		});
 
 //        ScrollPane scroller = new ScrollPane();
 //        scroller.setContent(listOfTaxonCandidates);
diff --git a/src/beastfx/app/util/Alert.java b/src/beastfx/app/util/Alert.java
index 7547550..9881f1a 100644
--- a/src/beastfx/app/util/Alert.java
+++ b/src/beastfx/app/util/Alert.java
@@ -196,6 +196,9 @@ public static Object showInputDialog(Parent parent,
 			dlg.setX(node.getX() + node.getWidth()/2);
 			dlg.setY(node.getY() + node.getHeight()/2);
 		}
+		if (option == null) {
+			return null;
+		}
 		String value = (String) option.get();
     	for (int i = 0; i < values.length; i++) {
     		if (value.equals(values[i])) {