ExtJs Gridpanel Window with checkbox selModel , on second opening doesn't display checkboxes

Question

I have a gridpanel with checkbox Selection Model inside a window.

On a button click handler, the window opens up the grid with checkboxes for the first time perfectly.

On opening it second time or later, the checkboxes are not visible. I am going an explicit instance creation in the grid Ext.define().

  selModel: Ext.create('Ext.selection.CheckboxModel', {
    mode: 'SIMPLE',
    checkOnly: true,
    listeners: {
        selectionchange: function (model, selections) {
            if (selections.length > 10) {
                Ext.Msg.alert('Info', 'Max of only 10 selections allowed');

                for (var i = 10; i < selections.length; i++) {
                    var record = selections[i];
                    model.deselect(record, true);
                }
            }
        }
    }
})

where am I going wrong here ?

Update:

- inside the button handler - opening a form with input entries - on form submit - open a window with checkbox - grid inside the storeload

        checkGridStore.load({
                        scope: this,
                        callback: function (records, operation, success) {                               
                            var firstWindowWithCheckGrid= Ext.widget('gridwindow', {                                  
                                 id: 'firstWindowWithCheckGrid'
                            });
                            firstWindowWithCheckGrid.show();
                        }
                    });

Window config :

 Ext.define('Sample.view.GridWindow', {
extend: 'Ext.window.Window',
alias: 'widget.gridwindow',
height: 500,
width: 1500,
modal: true,
layout: 'fit',
forceFit: true,
listeners: {
    beforeshow: function (window) {
        window.doLayout();
    }
},
buttons: [
    {
        text: 'Submit',
        handler: function () {
            var selectedRows = Ext.getCmp('statusGrid').getSelectionModel().getSelection();

            // do something

            Ext.getCmp('firstWindowWithCheckGrid').close();


            // do something

            secondStore.load({
                scope: this,
                callback: function (records, operation, flag) {
                    if (records.length > 0) {
                        var secondWindowWithoutCheckGrid = Ext.create('GridWindow', {
                            id: 'statusWindow',
                            items: {
                                xtype: 'gridpanel'

                            },
                            buttons: [
                                {
                                    text: 'Close',
                                    handler: function () {
                                        secondWindowWithoutCheckGrid .close();
                                    }
                                }
                            ]
                        }).show();
                    }
                }
            });
        }
    },
    {
        text: 'Close',
        handler: function () {
            try {
                Ext.getCmp('firstWindowWithCheckGrid').close();
            } catch (error) {

            }
        }
    }
],
initComponent: function () {
    this.items = [
        {
            xtype: 'statusgrid',
            id: 'statusGrid'
        }
    ]
    this.callParent(arguments);
}

});

Grid Config:

 Ext.define('Sample.view.StatusGrid', {
extend: 'Ext.grid.Panel',
alias: 'widget.statusgrid',
multiSelect: true,
emptyText: 'No Matching Records',
stripeRows: true,
columnLines: true,
store: 'SomeStore',
autoScroll: true,
margin: '5 5 5 5',
selModel: Ext.create('Ext.selection.CheckboxModel', {
    mode: 'SIMPLE',
    listeners: {
        selectionchange: function (model, selections) {
            if (selections.length > 10) {
                Ext.Msg.alert('Info', 'Max of only 10 selections allowed');

                for (var i = 10; i < selections.length; i++) {
                    var record = selections[i];
                    model.deselect(record, true);
                }
            }
        }
    }
}),
columns: [
   // columns

]
initComponent: function () {
    this.callParent(arguments);
}

});

Answer 1

I fixed it this way - thanks @EvanTrimboli for the hint

1. I removed the selModel instance in the grid definition.

2. Inside the initComponent of the window config above, I create a new instance of the selModel config object and include it in the items -> grid instance so the checkboxes don't disappear anymore

   initComponent: function () {
   
   var selModel= Ext.create('Ext.selection.CheckboxModel', {
       mode: 'SIMPLE',
       hidden: true,
       listeners: {
           selectionchange: function (model, selections) {
               if (selections.length > 10) {
                   Ext.Msg.alert('Info', 'Max of only 10 selections allowed');
   
                   for (var i = 10; i < selections.length; i++) {
                       var record = selections[i];
                       model.deselect(record, true);
                   }
               }
           }
       }
   });
   
   this.items = [
   {
       xtype: 'statusgrid',
       id: 'statusGrid',
       selModel: selModel
   }
   ]
   this.callParent(arguments);
   }        
   

Thank you all for the help !!!