I have 2 panels, thumbnail panel in the "west" and a viewer panel in the "center" regions of a border layout. Based on a config, I want to remove the thumbnail panel and make sure the viewer panel takes up that area as well.
Am able to set the width and height correctly but viewer panel does not occupy the whole area since it is in the west region. Which layout should I use in this scenario ?

Ext.define("xcp.ivf.Viewer", {
extend: "Ext.Panel",
alias: 'widget.xcp_viewer',
width: 850,
height: 500,
layout: 'border',
xtype: 'panel',
width: 150,
height: 500,
region: 'west',
collapsible: true,
autoScroll: true,
margins:'5 5 5 0'
xtype: 'panel',
region: 'center',
margins:'5 5 5 0',