added final keywords
diff --git a/src/main/java/org/apache/log4j/chainsaw/color/ColorPanel.java b/src/main/java/org/apache/log4j/chainsaw/color/ColorPanel.java
index 0ff74cf..53e8f91 100644
--- a/src/main/java/org/apache/log4j/chainsaw/color/ColorPanel.java
+++ b/src/main/java/org/apache/log4j/chainsaw/color/ColorPanel.java
@@ -750,11 +750,11 @@
     }
 
     class SelectedIcon implements Icon {
-        private boolean isSelected;
-        private int width = 9;
-        private int height = 18;
-        private int[] xPoints = new int[4];
-        private int[] yPoints = new int[4];
+        private final boolean isSelected;
+        private final int width = 9;
+        private final int height = 18;
+        private final int[] xPoints = new int[4];
+        private final int[] yPoints = new int[4];
 
         public SelectedIcon(boolean isSelected) {
             this.isSelected = isSelected;