ajax:command button call action method thrice

[ssher]

Hello

I am using ajax:command button onto which i call clearform methiod to reset form fields this button also reRender other components. problem is that method define in action attribute is call twice or some times thrice. i made many hit and trials but use lesss ....

<ajax:commandButton id="btn_reset" value="Reset" ajaxSingle="true" limitToList="true" action="#{orgTreeManager.clearForm}" reRender="panel_crud,txt_msg,btn_save" styleClass="button" />

public void clearForm(){

        this.hospitalCode = "";

        this.parentCode = "";

        this.orgCode = "";

        this.orgName = "";

        this.orgAddress = "";

        this.orgDesc = "";

        this.orgPhoneno = "";

        this.orgFax = "";

        this.orgEmail = "";

        this.orgStatus = "";

        this.orgType = "";

        this.message = "";

        this.nodesList.clear();

        this.mode = "";

        this.orgTreeEntity = null;

        this.parentNodeEntity = null;

        this.levelList.clear();       

    }

any help is highly appreciated