WPF C# Set visibility binding in code behind for framework element

Question

i have a problem binding the visibility property in code behind and really hope, you can help me.

I create a data grid column with a button. The tag property of the button is already binded to the data grid column value (text). I now want to set a visibility binding for the button, so that the button is hidden, when the text (in the Tag property) is empty. Unfortunately, nothing happened when the button tag is empty. The breakpoint in the converter never reaches.

// Create new column with a button content (this works!)
DataGridTemplateColumn dgButtonColumn = new DataGridTemplateColumn();
dgButtonColumn.CellTemplate = new DataTemplate(typeof(Button));
FrameworkElementFactory fefButton = new FrameworkElementFactory(typeof(Button));

// Set Content property (this works!)
fefButton.SetValue(Button.ContentProperty, "Text123");

// Bind Tag property (this works!)
Binding binding = new Binding(sqlColumnName) { UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged };
fefButton.SetBinding(Button.TagProperty, binding);

// Bind Visibility property **(this doesn't work!)**
Binding bindingVisibility = new Binding("Tag") { UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged, Converter = new Converter.TextNotEmptyToVisibilityConverter() };
bindingEnable.Source = fefButton;
fefButton.SetBinding(Button.VisibilityProperty, bindingVisibility);

For better understanding here the code of my converter class:

namespace ABC.Converter
{
    public class TextNotEmptyToVisibilityConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            return string.IsNullOrEmpty(value.ToStr()) ? Visibility.Hidden : Visibility.Visible;
        }

        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            throw new NotImplementedException();
        }
    }
}

Can you help me fixing it, so that the button will automatically disappears, when the Tag value is empty?

Thank you so much!