diff --git a/ganttzk/src/main/java/org/zkoss/ganttz/timetracker/TimeTracker.java b/ganttzk/src/main/java/org/zkoss/ganttz/timetracker/TimeTracker.java
index f7b55c0d2..802833c77 100644
--- a/ganttzk/src/main/java/org/zkoss/ganttz/timetracker/TimeTracker.java
+++ b/ganttzk/src/main/java/org/zkoss/ganttz/timetracker/TimeTracker.java
@@ -129,7 +129,7 @@ public class TimeTracker {
         return datesMapper;
     }
 
-    public void goToNextDetailLevel() {
+    public void zoomIncrease() {
         detailLevel = detailLevel.next();
         invalidatingChangeHappened();
     }
@@ -139,7 +139,7 @@ public class TimeTracker {
         fireZoomChanged();
     }
 
-    public void goToPreviousDetailLvel() {
+    public void zoomDecrease() {
         detailLevel = detailLevel.previous();
         invalidatingChangeHappened();
     }
diff --git a/ganttzk/src/main/java/org/zkoss/ganttz/timetracker/TimeTrackerComponent.java b/ganttzk/src/main/java/org/zkoss/ganttz/timetracker/TimeTrackerComponent.java
index 0e0bc2b4d..eaa592a38 100644
--- a/ganttzk/src/main/java/org/zkoss/ganttz/timetracker/TimeTrackerComponent.java
+++ b/ganttzk/src/main/java/org/zkoss/ganttz/timetracker/TimeTrackerComponent.java
@@ -131,13 +131,13 @@ public abstract class TimeTrackerComponent extends HtmlMacroComponent {
 
     public void onIncrease(int offset) {
         double daysOffset = getDaysFor(offset);
-        getTimeTracker().goToNextDetailLevel();
+        getTimeTracker().zoomIncrease();
         changeDetailLevel(daysOffset);
     }
 
     public void onDecrease(int offset) {
         double daysOffset = getDaysFor(offset);
-        getTimeTracker().goToPreviousDetailLvel();
+        getTimeTracker().zoomDecrease();
         changeDetailLevel(daysOffset);
     }
 
diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/AdvancedAllocationController.java b/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/AdvancedAllocationController.java
index 65b33f6a8..4aa9a1023 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/AdvancedAllocationController.java
+++ b/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/allocation/AdvancedAllocationController.java
@@ -73,11 +73,11 @@ public class AdvancedAllocationController extends GenericForwardComposer
     }
 
     public void onClick$zoomIncrease() {
-        timeTracker.goToNextDetailLevel();
+        timeTracker.zoomIncrease();
     }
 
     public void onClick$zoomDecrease() {
-        timeTracker.goToPreviousDetailLvel();
+        timeTracker.zoomDecrease();
     }
 
     private ICellForDetailItemRenderer<FakeColumn, FakeDataLeft> getLeftRenderer() {