diff --git a/ImageGallery/src/org/sleuthkit/autopsy/imagegallery/OnStart.java b/ImageGallery/src/org/sleuthkit/autopsy/imagegallery/OnStart.java
index c3bd1588fe..b222b2bc7c 100644
--- a/ImageGallery/src/org/sleuthkit/autopsy/imagegallery/OnStart.java
+++ b/ImageGallery/src/org/sleuthkit/autopsy/imagegallery/OnStart.java
@@ -22,8 +22,8 @@ import org.sleuthkit.autopsy.coreutils.Logger;
 
 /**
  *
- * The {@link OnStart} annotation tells NetBeans to invoke this class's
- * {@link OnStart#run()} method
+ * The {@link org.openide.modules.OnStart} annotation tells NetBeans to invoke
+ * this class's {@link OnStart#run()} method
  */
 @org.openide.modules.OnStart
 public class OnStart implements Runnable {
@@ -31,7 +31,7 @@ public class OnStart implements Runnable {
     static private final Logger LOGGER = Logger.getLogger(OnStart.class.getName());
 
     /**
-
+     *
      *
      * This method is invoked by virtue of the {@link OnStart} annotation on the
      * {@link ImageGalleryModule} class
diff --git a/ImageGallery/src/org/sleuthkit/autopsy/imagegallery/gui/navpanel/GroupTreeCell.java b/ImageGallery/src/org/sleuthkit/autopsy/imagegallery/gui/navpanel/GroupTreeCell.java
index d38916aef2..8e28fd91f7 100644
--- a/ImageGallery/src/org/sleuthkit/autopsy/imagegallery/gui/navpanel/GroupTreeCell.java
+++ b/ImageGallery/src/org/sleuthkit/autopsy/imagegallery/gui/navpanel/GroupTreeCell.java
@@ -18,6 +18,7 @@
  */
 package org.sleuthkit.autopsy.imagegallery.gui.navpanel;
 
+import java.util.Objects;
 import static java.util.Objects.isNull;
 import java.util.Optional;
 import javafx.application.Platform;
@@ -66,11 +67,13 @@ class GroupTreeCell extends TreeCell<TreeNode> {
     @Override
     protected synchronized void updateItem(final TreeNode tNode, boolean empty) {
         //if there was a previous group, remove the listener
-        Optional.ofNullable(getItem())
-                .map(TreeNode::getGroup)
-                .ifPresent((DrawableGroup t) -> {
-                    t.fileIds().removeListener(listener);
-                });
+        if (Objects.nonNull(listener)) {
+            Optional.ofNullable(getItem())
+                    .map(TreeNode::getGroup)
+                    .ifPresent((DrawableGroup t) -> {
+                        t.fileIds().removeListener(listener);
+                    });
+        }
 
         super.updateItem(tNode, empty);