How to assign both Watermark and a custom property to a TextBox's Text property? (MahApps)

Question

I'm having problems with creating a suitable watermark in my TextBox.

I use MahApps in my project, and as long as I don't bind 'Text' to my custom property, all works fine.

But I need to trace the changes in the TextBox, and so I bind the Text property like this:

<TextBox controls:TextboxHelper.Watermark="Enter text here..." Text="{Binding Path=MyProperty}" />

In this case, the watermark property stops working, the watermark text doesn't disappear when I start typing.

How can it be helped? Thanks!

UPDATE Here's the window of the sample made by har07. In the lower unbound TextBox the watermark works as expected. However, when I try to type smth in the first TextBox, the watermark is still there.

UPDATE2 Just in case someone will make the same mistake - appeared I was indeed setting my property in code while initializing the window, and that was the reason the watermark wasn't working. Now, thanks to har07, all is fine.

Answer 1

As I said in comment, there shouldn't be any problem setting watermark along with Text binding. I made simple test using 2 textboxes, one with Text property bound and the other not bound. Both are showing same behavior : watermark text replaced by typed text, and get dimmed upon textbox lost focus.

//View
<Controls:MetroWindow x:Class="WpfMahApps.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:Controls="clr-namespace:MahApps.Metro.Controls;assembly=MahApps.Metro"
        xmlns:local="clr-namespace:WpfMahApps"
        Title="StackOverflow" Height="500" Width="625"
        WindowStartupLocation="CenterScreen">
    <Grid>
        <Grid.DataContext>
            <local:Person/>
        </Grid.DataContext>
        <StackPanel>
            <TextBox Text="{Binding Name}" Controls:TextboxHelper.Watermark="Enter text here...."/>
            <TextBox Controls:TextboxHelper.Watermark="Enter text here too...."/>
        </StackPanel>
    </Grid>
</Controls:MetroWindow>

//Model (I'm using MvvmLight for implementation of INPC)
public class Person : ObservableObject
{
    private string _name = "Default Name";
    public String Name
    {
        get { return _name; }
        set
        {
            _name = value;
            RaisePropertyChanged(() => Name);
        }
    }
}

Download test project