QQmlApplicationEngine::retranslate() call invalidates DelegateModelGroup filtering

Hi!

I'm using a DelegateModelGroup inside a DelegateModel to filter some items of a GridView.

Besides, my application needs to be translated into several languages.

When I change the language by calling retranslate() on my QQmlApplicationEngine, all the items disappear...

I saw the following limitation in the documentation of QQmlApplicationEngine::retranslate:

Note: Due to a limitation in the implementation, this function refreshes all the engine's bindings, not only those that use strings marked for translation. This may be optimized in a future release.

As DelegateModelGroup' use is based on its 'name' property (which is a string), I think the issue come from there.

Steps to reproduce

Attached files are a minimal CMake project that shows the issue. Here are the steps to reproduce: 

mkdir build
cd build
cmake -DCMAKE_PREFIX_PATH=/path/to/your/Qt/gcc_64 ..
make -j 6

 Launch the 'my_target' executable and click the 'Translate' button.

--> all items in the GridView disappear