JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" type="text/css" href="//cdn.sencha.io/ext-4.1.0-gpl/resources/css/ext-all-debug.css" />

JavaScript

var data = [
{
    yearOne: 1,
    yearTwo: 1
}, {
    yearOne: 1,
    yearTwo: 1
}, {
    yearOne: 1,
    yearTwo: 1
}

];

/* MODEL */
Ext.define('YrModel', {
    extend: 'Ext.data.Model',
    fields: [{
        name: 'yearOne',
        type: 'int'
    }, {
        name: 'yearTwo',
        type: 'int'
    }],
});
/* STORE */
Ext.create('Ext.data.Store', {
    storeId: 'YrStore',
    model: "YrModel",
    data: data,
    autoLoad: true,
    proxy: {
        type: 'memory',
        reader: {
            type: 'json'
        }
    }
});
/* COMBOBOX STORE */
var comboboxStore = Ext.create('Ext.data.Store', {
    fields: ['abbr', 'name'],
    data : [
        {"abbr":"yearOne", "name":"Year One"},
        {"abbr":"yearTwo", "name":"Year Two"}
    ]
});
/* COMBOBOX */
var combobox = Ext.create('Ext.form.ComboBox', {
                fieldLabel: 'Choose a year',
                store: comboboxStore,
                queryMode: 'local',
                editable: false,
                displayField: 'name',
                valueField: 'abbr'
});

/* LISTENER TO COMBOBOX SELECT EVENT */
combobox.on({
    select: onComboboxSelect
});

/* METHOD THAT HANDLE THE COMBOBOX SELECT EVENT */
function onComboboxSelect(combo, records){
    var yearSelectValue = null;
    var yearSelected = (records.length > 0) 
                        ? records[0].get('abbr') 
                        : null;
    
    var selectedRecords = Ext.getCmp('yearGrid').getSelectionModel().getSelection();
    
    Ext.getStore('YrStore').each(function(record, index, count) {
        yearSelectValue = record.get(yearSelected);
        record.set(yearSelected, yearSelectValue + 1);
     });
    
    Ext.getCmp('yearGrid').getSelectionModel().select(selectedRecords);
}

/* GRID */
Ext.create('Ext.grid.Panel', {
    id: 'yearGrid',
    title: 'Year Data',
    renderTo: Ext.getBody(),
    store: Ext.getStore('YrStore'),
    selModel: Ext.create('Ext.selection.CheckboxModel'),
    viewConfig:{
       ...