Overriding font in custom Visual Studio editor

The problem is in making custom editor inside VS extension look differently than the current theme dictates. The editor is hosted inside a dialog and should have the same font the hosting dialog defines.

The content type of the editor is defined like this: 

    [Export]
    [Name("MyContent")]
    [BaseDefinition("code")]
    public static readonly ContentTypeDefinition ExportContentTypeDefinition = null;

And there is a classification type definition:

    [Export]
    [Name("MyContentText")]
    [BaseDefinition("text")]
    public static readonly ClassificationTypeDefinition MyTextDefinition = null;

The classifier provider is defined as below:

    [Export(typeof(IClassifierProvider))]
    [ContentType("MyContent")]
    public class ClassifierProvider : IClassifierProvider
    {
        [Import]
        public IClassificationTypeRegistryService ClassificationTypesRegistry { get; set; }

        public IClassifier GetClassifier(ITextBuffer textBuffer)
        {
            return new Classifier(
                ClassificationTypesRegistry.GetClassificationType("MyContentText"));
        }
    }

While the classifier just provides the same format for any snapshot:

    public class Classifier : IClassifier
    {
        private readonly IClassificationType _classificationType;

        public Classifier(IClassificationType classificationType)
        {
            _classificationType = classificationType;
        }

        public IList<ClassificationSpan> GetClassificationSpans(SnapshotSpan span)
        {
            return new [] { new ClassificationSpan(span, _classificationType)};
        }

        public event EventHandler<ClassificationChangedEventArgs> ClassificationChanged;
    }

Now, in code, while creating the editor, I'm trying to override the properties of the matchingIClassificationFormatMap:

    var contentType = contentTypeRegistryService.GetContentType("MyContent");
    var textBuffer = textBufferFactoryService.CreateTextBuffer(initialText, contentType);
    var textView = textEditorFactoryService.CreateTextView(textBuffer);

    ...

    var formatMap = classificationFomatMapService
        .GetClassificationFormatMap("MyContentText");

    formatMap.DefaultTextProperties = formatMap.DefaultTextProperties
        .SetFontRenderingEmSize(dialog.FontSize)
        .SetTypeface(
            new Typeface(
                dialog.FontFamily,
                dialog.FontStyle,
                dialog.FontWeight,
                dialog.FontStretch));

However, the change doesn't affect my editor instance.

Moreover, the format map returned from the classificationFomatMapService.GetClassificationFormatMap(ITextView) overload is different from the one returned from the overload I use above. And changing this another instance of format also affects all the code editors in the running Visual Studio instance, so I have to conclude that despite my efforts thetextView somehow maps to the default editor's classification.

My question is: what should I do in order to control text appearance of a custom editor designated for a custom content type?