wpf password box hint/placeholder text

<Style x:Key="HintedPasswordBox" TargetType="{x:Type PasswordBox}">
    <Setter Property="PasswordChar" Value="●" />
    <Setter Property="Background" Value="{DynamicResource TextBox.Static.Background}" />
    <Setter Property="BorderBrush" Value="{DynamicResource TextBox.Static.Border}" />
    <Setter Property="Foreground" Value="{DynamicResource AREghZyBrush.Foreground.Static}" />
    <Setter Property="BorderThickness" Value="1" />
    <Setter Property="KeyboardNavigation.TabNavigation" Value="None" />
    <Setter Property="HorizontalContentAlignment" Value="Left" />
    <Setter Property="FocusVisualStyle" Value="{x:Null}" />
    <Setter Property="AllowDrop" Value="true" />
    <Setter Property="ScrollViewer.PanningMode" Value="VerticalFirst" />
    <Setter Property="Stylus.IsFlicksEnabled" Value="False" />
    <Setter Property="ap:PasswordAttachedProperty.ListenToLength" Value="True"/>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type PasswordBox}">
                <Grid>
                    <Border x:Name="border" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" SnapsToDevicePixels="True">
                        <ScrollViewer x:Name="PART_ContentHost" Focusable="false" HorizontalScrollBarVisibility="Hidden" VerticalScrollBarVisibility="Hidden" />
                    </Border>
                    <TextBlock IsHitTestVisible="False"
                               Text="{TemplateBinding Tag}"
                               x:Name="PART_Placeholder"
                               FontFamily="{TemplateBinding FontFamily}"
                               FontSize="{TemplateBinding FontSize}"
                               Margin="3 0 0 0"
                               Padding="{TemplateBinding Padding}"
                               VerticalAlignment="Center"
                               HorizontalAlignment="{TemplateBinding HorizontalAlignment}"
                               Foreground="{DynamicResource AREghZyBrush.Foreground.Disabled}">
                        <TextBlock.Style>
                            <Style TargetType="{x:Type TextBlock}">
                                <Setter Property="Visibility" Value="Collapsed"/>
                                <Style.Triggers>
                                    <DataTrigger Binding="{Binding (ap:PasswordAttachedProperty.InputLength), RelativeSource={RelativeSource TemplatedParent}}" Value="0">
                                        <Setter Property="Visibility" Value="Visible"/>
                                    </DataTrigger>
                                    <MultiDataTrigger>
                                        <MultiDataTrigger.Conditions>
                                            <Condition Binding="{Binding IsFocused, RelativeSource={RelativeSource TemplatedParent}}" Value="True"/>
                                            <Condition Binding="{Binding (ap:TextHinting.ShowWhenFocused), RelativeSource={RelativeSource TemplatedParent}}" Value="False"/>
                                        </MultiDataTrigger.Conditions>
                                        <MultiDataTrigger.Setters>
                                            <Setter Property="Visibility" Value="Collapsed"/>
                                        </MultiDataTrigger.Setters>
                                    </MultiDataTrigger>
                                </Style.Triggers>
                            </Style>
                        </TextBlock.Style>
                    </TextBlock>
                </Grid>
                <ControlTemplate.Triggers>
                    <Trigger Property="IsEnabled" Value="false">
                        <Setter Property="Opacity" TargetName="border" Value="0.56" />
                    </Trigger>
                    <Trigger Property="IsMouseOver" Value="true">
                        <Setter Property="BorderBrush" TargetName="border" Value="{DynamicResource TextBox.MouseOver.Border}" />
                    </Trigger>
                    <Trigger Property="IsKeyboardFocused" Value="true">
                        <Setter Property="BorderBrush" TargetName="border" Value="{DynamicResource TextBox.Focus.Border}" />
                    </Trigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
    <Style.Triggers>
        <MultiTrigger>
            <MultiTrigger.Conditions>
                <Condition Property="IsInactiveSelectionHighlightEnabled" Value="true" />
                <Condition Property="IsSelectionActive" Value="false" />
            </MultiTrigger.Conditions>
            <Setter Property="SelectionBrush" Value="{DynamicResource TextBox.Selection.Inactive}" />
        </MultiTrigger>
    </Style.Triggers>
</Style>

public class PasswordAttachedProperty {
    public static readonly DependencyProperty ListenToLengthProperty =
        DependencyProperty.RegisterAttached(
            "ListenToLength",
            typeof(bool),
            typeof(PasswordAttachedProperty),
            new FrameworkPropertyMetadata(false, PropertyChangedCallback));

    private static void PropertyChangedCallback(DependencyObject d, DependencyPropertyChangedEventArgs e) {
        if (e.NewValue == e.OldValue) {
            return;
        }

        if (d is PasswordBox box) {
            if ((bool) e.NewValue) {
                // just in case...
                box.PasswordChanged -= BoxOnPasswordChanged;
                box.PasswordChanged += BoxOnPasswordChanged;
            }
            else {
                box.PasswordChanged -= BoxOnPasswordChanged;
            }
        }
        else {
            throw new Exception("DependencyObject is not a password box. It is '" + (d == null ? "null" : d.GetType().Name) + '\'');
        }
    }

    public static readonly DependencyProperty InputLengthProperty =
        DependencyProperty.RegisterAttached(
            "InputLength",
            typeof(int),
            typeof(PasswordAttachedProperty),
            new FrameworkPropertyMetadata(0));

    public static bool GetListenToLength(PasswordBox box) {
        return (bool) box.GetValue(ListenToLengthProperty);
    }

    public static void SetListenToLength(PasswordBox box, bool value) {
        box.SetValue(ListenToLengthProperty, value);
    }

    public static int GetInputLength(PasswordBox box) {
        return (int) box.GetValue(InputLengthProperty);
    }

    public static void SetInputLength(PasswordBox box, int value) {
        box.SetValue(InputLengthProperty, value);
    }

    private static void BoxOnPasswordChanged(object sender, RoutedEventArgs e) {
        SetInputLength((PasswordBox) sender, ((PasswordBox) sender).SecurePassword.Length);
    }
}

public static class TextHinting {
    public static readonly DependencyProperty ShowWhenFocusedProperty =
        DependencyProperty.RegisterAttached(
            "ShowWhenFocused",
            typeof(bool),
            typeof(TextHinting),
            new FrameworkPropertyMetadata(false));

    public static void SetShowWhenFocused(Control control, bool value) {
        if (control is TextBoxBase || control is PasswordBox) {
            control.SetValue(ShowWhenFocusedProperty, value);
        }

        throw new ArgumentException("Control was not a textbox", "control");
    }

    public static bool GetShowWhenFocused(Control control) {
        if (control is TextBoxBase || control is PasswordBox) {
            return (bool) control.GetValue(ShowWhenFocusedProperty);
        }

        throw new ArgumentException("Control was not a textbox", "control");
    }
}

https://github.com/AngryCarrot789/REghZyAccountManagerV6