The issue is that Windows 8.1 mobile browser is detected as both IE and Chrome, which means that certain objects are not initialized, but expected to be available.
The initialize code goes like this:
if(Ext.isIE) ...
else if (Ext.isChrome) ...
and the code that requires the object goes like this:
if(Ext.isChrome) ...
This code only works until a browser is detected as both IE and Chrome.
To check whether you are affected by exactly this, please do the following:
- Open the sencha touch app in IE11.
- Open the developer tab.
- Switch "Profile" to "Mobile and "User Agent" to "IE 11 Mobile / Windows 8.1"
- Your app should reload into failure.
When trying exactly this with official Kitchen Sink, you will find that this is a problem of the Sencha Touch framework. I have already filed two bug reports to that regard, but they are ignored by Sencha, so please don't expect anything from them.