featureFilter on GeoExt.data.FeatureStore has no effect

[schmity]

Hi,
the featureFilter config on Geoext.data.FeatureStore has no effect.
I use GeoExt 1.1 with ext-js 3.4.0 and OpenLayers 2.12.
The store uses a GeoExt.data.ProtocolProxy to get features from a WFS. On that store I set the featureFilter-configOption in order to only display (and request) a subset of the available features in the grid. However, the filter does not get evaluated and all features are requested and show up in the grid.
Attaching the filter to the protocol works fine.

Debugging GeoExt.data.FeatureStore, I find that the code to evaluate this.featureFilter in onFeaturesAdded()-method never gets executed.

Here is the code for the grid panel:
gridPanel = new Ext.grid.GridPanel({
ref: 'featuregrid',
title: 'Tabellenansicht Parkhäuser',
region: 'north',
height: 200,
sm: new GeoExt.grid.FeatureSelectionModel(),
store: new GeoExt.data.FeatureStore({
fields: [
{name: "name", type: "string"},
{name: "art", type: "string"},
{name: "frei", type: "string"},
{name: "received", type: "string"}
],
proxy: new GeoExt.data.ProtocolProxy({
protocol: new OpenLayers.Protocol.WFS({
url: "http://gateway.hamburg.de/OGCFassade/Test_HH_WFS_Fachdaten.aspx",
version: "1.1.0",
featureType: "verkehr_parkhaeuser",
featureNS: "http://www.deegree.org/app",
srsName: "EPSG:25832"
})
}),
featureFilter: new OpenLayers.Filter.Spatial({
type: OpenLayers.Filter.Spatial.BBOX,
value: new OpenLayers.Bounds(563768,5932433,568001,5935608),
projection: "EPSG:25832"
}),
autoLoad: true
}),
columns: [
{header: "name", dataIndex: "name"},
{header: "Art", dataIndex: "art"},
{header: "Freie Stellplätze", dataIndex: "frei"},
{header: "Aktualität", dataIndex: "received"}
]
});

Best,
Sebastian