Ext.Ajax.timeout has no effect

Since I did migrate our solution to ExtJS 5 (5.0.0) the global setting for Ext.Ajax.timeout has no the ajax calls.

This code runs in a timeout after 30 seconds:

Code:

Ext.Ajax.timeout = 180000; // 3 minutes
Ext.onReady(function () {
    Ext.Ajax.request({
        url: 'longRunningTask',
        success: function (response) {
            alert('success');
        },
        failure: function (res, opts) {
            if (res.timedout) {
                alert('timeout');
            } else {
                alert('failure');
            }
        }
    });
});

This code not:

Code:

Ext.onReady(function () {
    Ext.Ajax.request({
        url: 'longRunningTask',
        success: function (response) {
            alert('success');
        },
        timeout: 180000,
        failure: function (res, opts) {
            if (res.timedout) {
                alert('timeout');
            } else {
                alert('failure');
            }
        }
    });
});