I have a panel with border layout. This panel has center region and a west region. In west region, there is a panel with border layout that contains 3 panels. See the picture below.

I use "split" so that the west region is re sizable using the splitter. The problem is, when I try to re size the west region, the inner panels are not re sized properly. See the picture below.

My code is very minimal and I see nothing wrong in it.
Here is the JSFiddle of my code And below is the code that generates these panels.
this.mainPanel = Ext.create('Ext.panel.Panel', {
layout: 'border',
height: 1000,
width: 1400,
items: [{
xtype: 'panel',
region: 'center',
layout: 'border',
id: 'center-panel',
items: [{
xtype: 'panel',
layout: 'border',
region: 'center',
items: [{
xtype: 'panel',
region: 'center',
id: 'grid-panel',
layout: 'fit'
}, {
xtype: 'panel',
id: 'south-panel',
region: 'south',
split: true,
title: 'Additional data represented by this event',
height: 200
}]
}]
}, {
xtype: 'panel',
ref: 'west_panel',
region: 'west',
split: true,
title: 'Show/Hide',
width: 300,
minWidth: 175,
maxWidth: 500,
items: [{
xtype: 'panel',
split: true,
collapsed: true,
title: 'Show/Hide by Time'
}, {
xtype: 'panel',
split: true,
collapsible: true,
title: 'Show/Hide by activity types and tags'
}, {
xtype: 'panel',
split: true,
collapsible: true,
title: 'Show/Hide by participant types and tags'
}]
}]
});
this.mainPanel.render(document.getElementById('example-grid'));
Any idea how I can fix this problem?
P.S. I am using ExtJS 4.2.1.883