diff --git a/ganttzk/src/main/resources/web/js/ganttz/TaskComponent.js b/ganttzk/src/main/resources/web/js/ganttz/TaskComponent.js
index 5d0f9ecbb..9c1b74b07 100644
--- a/ganttzk/src/main/resources/web/js/ganttz/TaskComponent.js
+++ b/ganttzk/src/main/resources/web/js/ganttz/TaskComponent.js
@@ -234,7 +234,7 @@ ganttz.TaskComponent = zk.$extends(zul.Widget, {
         jq('.task-labels',this.$n()).hide();
     },
     setClass : function(cssClass){
-        jq(this.$n()).addClass(cssClass);
+        jq(this.$n()).removeClass().addClass(cssClass);
     }
 },{
     //"Class" methods and properties