diff --git a/src/main/java/org/stt/gui/jfx/ImageButton.java b/src/main/java/org/stt/gui/jfx/ImageButton.java
index d21b4254..d54c5096 100644
--- a/src/main/java/org/stt/gui/jfx/ImageButton.java
+++ b/src/main/java/org/stt/gui/jfx/ImageButton.java
@@ -7,8 +7,8 @@
 import javafx.scene.input.MouseEvent;
 
 public class ImageButton extends Button {
-	private final String STYLE_NORMAL = "-fx-background-color: transparent; -fx-padding: 5, 5, 5, 5;";
-	private final String STYLE_PRESSED = "-fx-background-color: transparent; -fx-padding: 6 4 4 6;";
+	private static final String STYLE_NORMAL = "-fx-background-color: transparent; -fx-padding: 5, 5, 5, 5;";
+	private static final String STYLE_PRESSED = "-fx-background-color: transparent; -fx-padding: 6 4 4 6;";
 
 	public ImageButton(Image image) {
 		setGraphic(new ImageView(image));