extjs中treepanel移动数据如何更改为正在移动提示

viewConfig: {
	    	
	plugins: {
	            
		ptype  : 'treeviewdragdrop',
	            
		dragText : "{0} 正在移动{1}"
	        
	}
	   
	,listeners:{
	        	
	beforedrop:function(node, data, overModel, dropPosition,dropFunction, options){
	    

    	},
	        	
	drop : function(node, data, overModel, dropPosition, options) {
	       
 	}
}