After a call to reconfigure, loadmask is lost. I believe that, instead of Ext.apply, it should use Ext.applyIf. So, instead of
Code:
this.loadMask = new Ext.LoadMask(this.container, Ext.apply({store:dataSource}, this.loadMask));
should be
Code:
this.loadMask = new Ext.LoadMask(this.container, Ext.applyIf({store:dataSource}, this.loadMask)) ;
Tom