diff --git a/ganttzk/src/main/java/org/zkoss/ganttz/LeftTasksTreeRow.java b/ganttzk/src/main/java/org/zkoss/ganttz/LeftTasksTreeRow.java
index e24020521..8669185ec 100644
--- a/ganttzk/src/main/java/org/zkoss/ganttz/LeftTasksTreeRow.java
+++ b/ganttzk/src/main/java/org/zkoss/ganttz/LeftTasksTreeRow.java
@@ -356,7 +356,9 @@ public class LeftTasksTreeRow extends GenericForwardComposer {
         getNameBox().setValue(task.getName());
         getNameBox().setTooltiptext(task.getName());
         getStartDateBox().setValue(task.getBeginDate());
+        getStartDateBox().setDisabled(!task.canBeExplicitlyMoved());
         getEndDateBox().setValue(task.getEndDate());
+        getEndDateBox().setDisabled(!task.canBeExplicitlyResized());
         getStartDateTextBox().setValue(asString(task.getBeginDate()));
         getEndDateTextBox().setValue(asString(task.getEndDate()));
     }