问OpenLayers.Controls.DrawFeature激活/停用失败

EN

this.active --> true
this.deactivate() --> true
this.activate() --> true
this.deactivate() --> false

JS FILE:
var map;
var editing_toolbar_polygon=null;
var editing_toolbar_vector=null;
var drag_control=null;
var vectors;
var polygon_layer=null;
var epsg900913 = new OpenLayers.Projection('EPSG:900913');
var epsg4326 = new OpenLayers.Projection('EPSG:4326');
//var epsg900913 = new OpenLayers.Projection('EPSG:900913');
// var epsg4326 = new OpenLayers.Projection('EPSG:4326');
var line_control;
var polygon_control;
var renderer;
function initialize() {
    line_control, renderer=OpenLayers.Util.getParameters(window.location.href).renderer;
    renderer= (renderer) ? [renderer] : OpenLayers.Layer.Vector.prototype.renderers;
    // Create the map object
    map = new OpenLayers.Map('map');
     //Create a Google layer
    var gmap = new OpenLayers.Layer.Google(
        "Google Streets", // the default
        {
            numZoomLevels: 20,
            projection: new OpenLayers.Projection("EPSG:900913")
        }
    );
    var wms = new OpenLayers.Layer.WMS( "OpenLayers WMS",
             "http://vmap0.tiles.osgeo.org/wms/vmap0?", {layers: 'basic',
    projection: new OpenLayers.Projection("EPSG:4326")});

    var mystyle=new OpenLayers.StyleMap({
        "default": new OpenLayers.Style({
             fillColor: "#66ccff",
             strokeColor: "#3399ff",
             graphicZIndex: 2,
             strokeWidth: 5,
         }),
        "temporary": new OpenLayers.Style({
             fillColor:"#3399ff",
             strokeColor: "#3399ff",
             strokeWidth:5,  
             pointRadius:10

         })        
    });
    polygon_layer=new OpenLayers.Layer.Vector(
        "Polygon Layer",
        {
            //renderers:renderer,
        }
    );

    vectors= new OpenLayers.Layer.Vector(
        "Vector Layer",
        {
            //renderers:renderer,
        }
    );

    editing_toolbar_polygon=new OpenLayers.Control.EditingToolbar(polygon_layer);
    editing_toolbar_vector=new OpenLayers.Control.EditingToolbar(vectors);
    map.addLayers([gmap,wms,vectors,polygon_layer]);
    map.addControl(new OpenLayers.Control.LayerSwitcher());
    //map.addControl(new OpenLayers.Control.MousePosition());
    map.addControl(editing_toolbar_polygon); 
    map.addControl(editing_toolbar_vector); 
    editing_toolbar_vector.deactivate();
    //for the drag control to work you need to activate it
    drag_control=new OpenLayers.Control.DragFeature(vectors);
    map.addControl(drag_control);
    find_control(editing_toolbar_polygon.getControlsByClass(new RegExp(".*DrawFeature")),"Point").events.register("activate",null,function(e){
      //ERROR HERE
        this.deactivate();
        var picked_button=find_same_control(editing_toolbar_vector.controls,e.object);
        change_layer(polygon_layer,vectors);
        change_control(editing_toolbar_polygon,editing_toolbar_vector);
        picked_button.activate();
    });
    find_control(editing_toolbar_polygon.getControlsByClass(new RegExp(".*DrawFeature")),"Path").events.register("activate",null,function(e){
      //ERROR HERE
        this.deactivate();
        var picked_button=find_same_control(editing_toolbar_vector.controls,e.object);
        change_layer(polygon_layer,vectors);
        change_control(editing_toolbar_polygon,editing_toolbar_vector);
        picked_button.activate();
    });
    find_control(editing_toolbar_vector.getControlsByClass(new RegExp(".*DrawFeature")),"Polygon").events.register("activate",null,function(e){
      //ERROR HERE
        this.deactivate();
        var picked_button=find_same_control(editing_toolbar_polygon.controls,e.object);
        change_layer(vectors,polygon_layer);
        change_control(editing_toolbar_vector,editing_toolbar_polygon);
        picked_button.activate();
    });
    polygon_layer.events.register("beforefeatureadded",null,function(e){  
            polygon_layer.removeAllFeatures();
    });
   // line_control=new OpenLayers.Control.DrawFeature(vectors,OpenLayers.Handler.Path);
    //polygon_control=new OpenLayers.Control.DrawFeature(vectors,OpenLayers.Handler.RegularPolygon);
    //map.addControl(line_control);
    //line_control.activate();
    //map.addControl(polygon_control);
    //polygon_control.activate();
    // Zoom to Vancouver, BC
    map.setCenter(new OpenLayers.LonLat(-123.12, 49.28).transform(epsg4326, epsg900913), 13);         

}

function change_layer(current_layer,next_layer){
   current_layer.setVisibility(false);
   next_layer.setVisibility(true); 
}
function change_control(current_control,next_control){
   current_control.deactivate();
   map.addControl(next_control);
}

//use this when you want to find a specific control type:
// DrawFeature cntrol has many types, Line, Polygon, Point.
// So what you do is pass an array of DrawFeature controls and a type(string), lets say "Point",
// then this function will return a DrawFeature thats specifically for drawing points
function find_control(controls,type){
    var control;
    for(var x in controls){
        if(controls[x].displayClass.search(new RegExp(type+"$"))>0){
             return controls[x];
        }
    }
    return -1;
}