diff --git a/bootstrap-core/src/main/java/de/agilecoders/wicket/core/markup/html/bootstrap/panel/PanelType.java b/bootstrap-core/src/main/java/de/agilecoders/wicket/core/markup/html/bootstrap/panel/PanelType.java
index cfa6431b2..686b71733 100644
--- a/bootstrap-core/src/main/java/de/agilecoders/wicket/core/markup/html/bootstrap/panel/PanelType.java
+++ b/bootstrap-core/src/main/java/de/agilecoders/wicket/core/markup/html/bootstrap/panel/PanelType.java
@@ -51,9 +51,9 @@ public enum PanelType
 	Transparent(BackgroundColorBehavior.Color.Transparent, ColorBehavior.Color.Body, null);
 
 	
-	private BackgroundColorBehavior.Color backgroundColor;
-	private ColorBehavior.Color textColor;
-	private BorderBehavior.Color borderColor;
+	private final BackgroundColorBehavior.Color backgroundColor;
+	private final ColorBehavior.Color textColor;
+	private final BorderBehavior.Color borderColor;
 	
 	private PanelType(BackgroundColorBehavior.Color backgroundColor, ColorBehavior.Color textColor, Color borderColor) {
 		this.backgroundColor = backgroundColor;
diff --git a/bootstrap-samples/src/main/java/de/agilecoders/wicket/samples/panels/PanelTypesPanel.java b/bootstrap-samples/src/main/java/de/agilecoders/wicket/samples/panels/PanelTypesPanel.java
index 6f93990b4..8f6af1172 100644
--- a/bootstrap-samples/src/main/java/de/agilecoders/wicket/samples/panels/PanelTypesPanel.java
+++ b/bootstrap-samples/src/main/java/de/agilecoders/wicket/samples/panels/PanelTypesPanel.java
@@ -2,23 +2,12 @@
 
 import java.util.Arrays;
 
-import org.apache.wicket.Component;
 import org.apache.wicket.markup.html.basic.Label;
-import org.apache.wicket.markup.html.image.ExternalImage;
-import org.apache.wicket.markup.html.link.Link;
 import org.apache.wicket.markup.html.list.ListItem;
 import org.apache.wicket.markup.html.list.PropertyListView;
 import org.apache.wicket.markup.html.panel.Panel;
-import org.apache.wicket.model.IModel;
-import org.apache.wicket.model.Model;
-
-import de.agilecoders.wicket.core.markup.html.bootstrap.button.BootstrapButton;
-import de.agilecoders.wicket.core.markup.html.bootstrap.button.Buttons;
 import de.agilecoders.wicket.core.markup.html.bootstrap.panel.PanelType;
 
-/**
- * @author Jan Ferko
- */
 public class PanelTypesPanel extends Panel {
 
 	public PanelTypesPanel(String id) {