Hello,
I have a multiselector configured and placed inside a window. I want be fully sized as much as window is being inside it iwth padding of 15px.
Here is my code, I have everything but this anchor thingy. Please let me know about it:

Code:
var addServiceWindow = new Ext.Window({
            title: 'Add Service',
            width: 450,
            minWidth: 450,
            layout: 'anchor',
            bodyStyle: 'padding:15px',
            modal: true,
            items:
            [
                new Ext.form.FormPanel({
                    id: 'addServiceWindowFormPanel',
                    header: false,
//                    baseCls: 'x-plain',
                    bodyStyle: 'padding:15px',
                    api: 
                    {
                        submit: Autotrack.Remote.addService
                    },
                    items:
                    [
                        {
                            fieldLabel: 'Service Name',
                            name: 'addServiceWindowServiceName',
                            id: 'addServiceWindowServiceName',
                            xtype: 'textfield',
                            anchor: '100%'
                        },
                        {
                            id: 'addServiceWindowPackage',
                            xtype: 'multiselect',
                            name: 'addServiceWindowPackage',
                            anchor: '100%',              // <------- Not working
                            store: packageComboboxStore,
                            valueField: 'PackageId',
                            displayField: 'PackageName',
                            idProperty: 'PackageId',
                            tbar:
                            [
                                {
                                    text: 'clear',
                                    handler: function(){
                                        Ext.getCmp('addServiceWindowPackages').reset();
	                                }
                                }
                            ]
                        }
                    ]
                })
            ],
            bbar: new Ext.ux.StatusBar(
            {
                items:
                [
                    {
                        text: 'Add',
                        handler: function()
                        {
                            var serviceName = Ext.getCmp('addServiceWindowServiceName').getValue();
                            var packageId = [];
                            packageId = Ext.getCmp('addServiceWindowPackage').getValue().split(',');
                            Autotrack.Remote.addService(serviceName,packageId, function(data, trans){
                                if(data == true)
                                {
                                    Ext.MessageBox.alert('Service Added Successfully', serviceName + ' Has Been Added To The Selected Package(s).');
                                }
                                else
                                {
                                    Ext.MessageBox.alert('Error', serviceName + ' Could Not Be Added To The Selected Package(s). Samed Named Service May Exist Already.');
                                }
                            });
                            addServiceWindow.close();
                        }
                    },
                    {
                        text: 'Cancel',
                        handler: function() {
                            addServiceWindow.close();
                        }
                    }
                ]
            })
        });