diff --git a/src/main/java/plugins/adufour/activecontours/ActiveContours.java b/src/main/java/plugins/adufour/activecontours/ActiveContours.java
index b70063ec2fbbd5a787734958c61395ada1712b10..c0a608ba72349617e3f6e33a804a3aa2af2c63fa 100644
--- a/src/main/java/plugins/adufour/activecontours/ActiveContours.java
+++ b/src/main/java/plugins/adufour/activecontours/ActiveContours.java
@@ -51,6 +51,7 @@ import plugins.adufour.blocks.lang.Block;
 import plugins.adufour.blocks.util.VarList;
 import plugins.adufour.ezplug.EzButton;
 import plugins.adufour.ezplug.EzException;
+import plugins.adufour.ezplug.EzGUI;
 import plugins.adufour.ezplug.EzGroup;
 import plugins.adufour.ezplug.EzPlug;
 import plugins.adufour.ezplug.EzStoppable;
@@ -1364,6 +1365,7 @@ public class ActiveContours extends EzPlug implements EzStoppable, Block
         int iter = 0;
         int nbConvergedContours = 0;
         boolean hasContour3d = false;
+        final EzGUI ui = getUI();  
 
         while (!globalStop && (nbConvergedContours < allContoursAtTimeT.size()))
         {
@@ -1392,12 +1394,12 @@ public class ActiveContours extends EzPlug implements EzStoppable, Block
             if (evolvingContoursAtTimeT.size() == 0)
                 break;
 
-            if (getUI() != null)
+            if (ui != null)
             {
                 if (nbConvergedContours == 0)
-                    getUI().setProgressBarValue(Double.NaN);
+                    ui.setProgressBarValue(Double.NaN);
                 else
-                    getUI().setProgressBarValue((double) nbConvergedContours / allContoursAtTimeT.size());
+                    ui.setProgressBarValue((double) nbConvergedContours / allContoursAtTimeT.size());
 
                 // getUI().setProgressBarMessage("" + iter); // slows down the AWT !!
             }