In the previous version it was possible to omit the columnWidth from the fieldset config.

In version 4.2 it is needed. It would be nice if it is still possible to omit the columnWidth. I generate fieldsets and I do not know beforehand how many fieldsets there are.



Code:
Ext.create('Ext.form.Panel', {
    title: 'Simple Form with FieldSets',
    labelWidth: 75, // label settings here cascade unless overridden
    url: 'save-form.php',
    frame: true,
    bodyStyle: 'padding:5px 5px 0',
    width: 550,
    renderTo: Ext.getBody(),
    layout: 'column', // arrange fieldsets side by side
    defaults: {
        bodyPadding: 4
    },
    items: [{
        // Fieldset in Column 1 - collapsible via toggle button
        xtype: 'fieldset',
       // columnWidth: 0.5,
        title: 'Fieldset 1',
        collapsible: true,
        defaultType: 'textfield',
        defaults: { anchor: '100%' },
        layout: 'anchor',
        items: [{
            fieldLabel: 'Field 1',
            name: 'field1'
        }, {
            fieldLabel: 'Field 2',
            name: 'field2'
}]
        }, {
            // Fieldset in Column 2 - collapsible via checkbox, collapsed by default, contains a panel
            xtype: 'fieldset',
            title: 'Show Panel', // title or checkboxToggle creates fieldset header
        //    columnWidth: 0.5,
            checkboxToggle: true,
            collapsed: true, // fieldset initially collapsed
            layout: 'anchor',
            items: [{
                xtype: 'panel',
                anchor: '100%',
                title: 'Panel inside a fieldset',
                frame: true,
                height: 52
}]
}]
            });