ExtJS columns renderer, row count and setLoading

Question

I have a grid.Panel, it is hidden by default. When I show it, it renders 100 lines and performs the function renderer, but if you call refresh() for this table, it will render only 49 lines, what do these numbers depend on and how to change them? Also wondering if there is an event when the lines are rendered to cause setLoading(false)?

grid.Panel:

extend: 'Ext.grid.Panel',
alias: 'widget.commongrid',

controller: 'commongrid-controller',
viewModel: {
    type: 'commongrid-model'
},

viewConfig: {
    enableTextSelection: true
},

enableColumnMove: false,
columns: [],
bind: {
    store: '{commonDetailStore}'
},

createGrid: function (columns, data) {
    var ctrl = this.getController();

    ctrl.createGrid(columns, data);
}

Controller code:

createGrid: function (columns, data) {
    var me = this,
        view = me.getView(),
        vm = me.getViewModel(),
        store = vm.getStore('commonDetailStore');

    columns = me.generateColumn(columns);

    view.reconfigure(columns);
    store.loadData(data);
},

generateColumn: function (columns) {
    return Ext.Array.map(columns, function (column, index) {
        return {
            'dataIndex': column,
            'text': column,
            'width': 150,
            'sortable': false,
            'resizable': true,
            'menuDisabled': true,
            'renderer': 'onCommonDetailedGridColumnRenderer'
        };
    });
}

grid.Model:

extend: 'Ext.app.ViewModel',

alias: 'viewmodel.commongrid-model',

stores: {
    commonDetailStore: {
        autoLoad: true,
        proxy: {
            type: 'localstorage'
        },
        fields: []
    }
}