how to clear checked rows after reload the grid panel with checkboxselectionmodle? I use this code, but the gird panel will reload 3 or 4 times . 
                    StoreConsist.Reload();
                    CheckboxSelectionModel sm = this.GridPanelConsist.GetSelectionModel() as CheckboxSelectionModel;
                    sm.DeselectAll();
the grid panel works well the first time I delete checked rows. After I triggered another item ,reload the girdpanel and the delete the rows ,it shows I checked null.