Today, I stumbled upon http://prop.erti.es/app/

I think it was the first Sencha Touch web app I came across which had a nice transition between startup/preloading and the app itself. I tried to do something similar but it's not that smooth at all.

Here is my example:

app.css

Code:
body.startup {    height: 100%;
    text-align: center;
}
index.html

Code:
<body class="startup">
        
        <div id="startup-loader" style="position: absolute; left: 50%; top: 50%; ">
            <img src="public/resources/img/loader.gif" alt="lade..."/>
        </div>
...

app.js

Code:
Ext.setup({
    onReady: function () {
        Ext.fly('startup-loader').remove();
        Ext.getBody().removeCls("startup");
    }
});
Any ideas how to avoid the white blink between the loader and app itself?