@Sencha explains the fix in this link.
ExtJs v4.1.1 or v4.2.1 Ext = { buildSettings:{ baseCSSPrefix: 'x-', scopeResetCSS: true } }; ExtJs v4.2.0 Ext.define('Ext.BorderBoxFix', { override: 'Ext.AbstractComponent', initStyles: function(targetEl) { this.callParent(arguments); if (Ext.isBorderBox && (!me.ownerCt || me.floating)) { targetEl.addCls(Ext.baseCSSPrefix + 'border-box'); } } }); Ext.onReady(function() { Ext.fly(document.documentElement).removeCls(Ext.baseCSSPrefix + 'border-box'); });
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