Hint Assist not disappearing when Text value is set on MaterialDesignDataGridTextColumnPopupEditingStyle

I am creating dynamic columns for my DataGrid, so I am creating a number of MaterialDataGridTextColumn in code behind. I am modifying the MaterialDesignDataGridTextColumnPopupEditingStyle to allow the TextBox to have a hint property:

Style style = (Style)FindResource("MaterialDesignDataGridTextColumnPopupEditingStyle");
var editingStyle = new Style(typeof(TextBox), style)
{
	Setters =
	{
		new Setter(HintAssist.HintProperty, "Enter Score"),
		new Setter(MarginProperty, new Thickness(8)),
	}
};

foreach (string name in columnNames)
{
	var binding = new Binding("Attributes[" + name + "].Value")
	{
		UpdateSourceTrigger = UpdateSourceTrigger.LostFocus,
		ValidatesOnDataErrors = true,
		StringFormat = "0.0;;#"
	};

	var mdTxtCol = new MaterialDataGridTextColumn
	{
		Header = name,
		Binding = binding,
		EditingElementStyle = editingStyle,
		ElementStyle = centerTextSetter,
	};
	caseGrid.Columns.Add(mdTxtCol);
}

This successfully produces the pop up like so:

And as you type a value in the textbox, the hint property disappears, as it should:

However, the problem is that when this cell re-enters the edit mode while it contains a value, the hint property should disappear, but it doesn’t:

As you can see, both the entered value and the hint property are shown.

[jcummings2]

I am experiencing this problem as well, although I am setting the Hint in XAML. It is easy to reproduce the issue with the Demo program by altering the EditingElementStyle of the Name column as follows:

<materialDesign:MaterialDataGridTextColumn Binding="{Binding Name}"
                                       Header="Name"
                                       >
        <materialDesign:MaterialDataGridTextColumn.EditingElementStyle>
            <Style BasedOn="{StaticResource MaterialDesignDataGridTextColumnPopupEditingStyle}" TargetType="{x:Type TextBox}" >
                <Setter Property="materialDesign:HintAssist.Hint" Value="Name Hint" />
            </Style>
        </materialDesign:MaterialDataGridTextColumn.EditingElementStyle>
</materialDesign:MaterialDataGridTextColumn>

This leads to the behavior @AmitBhatnagar24 noted previously. Here is a screencast illustrating the problem:

Note that the Hint disappears when typing anything in the box. It reappears, however, when selecting the cell again.

I believe the XAML is adding setters not replacing the entire set, so I think it avoids the issue that @Keboo mentioned.

[jcummings2]

See also Gitter chat about issue