Use a ValueConverter to break into the debugger when having Debug Databinding Issues in WPF. (From: http://www.wpftutorial.net/DebugDataBinding.html)

DatabindingDebugConverter.cs

using System;
using System.Diagnostics;
using System.Globalization;
using System.Windows.Data;

/// <summary>
/// This converter does nothing except breaking the
/// debugger into the convert method
/// </summary>
public class DatabindingDebugConverter : IValueConverter
{
    public object Convert(object value, Type targetType, 
        object parameter, CultureInfo culture)
    {
        Debugger.Break();
        return value;
    }
 
    public object ConvertBack(object value, Type targetType, 
        object parameter, CultureInfo culture)
    {
        Debugger.Break();
        return value;
    }
}

sampleuse1.xaml

<Window x:Class="DebugDataBinding.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:DebugDataBinding"
    Title="Window1" Height="300" Width="300">
 
    <Window.Resources>
        <local:DatabindingDebugConverter x:Key="debugConverter" />
    </Window.Resources>
 
    <StackPanel x:Name="stack">
        <TextBlock Text="{Binding ElementName=stack, Path=ActualWidth, 
                          Converter={StaticResource debugConverter}}" />
    </StackPanel>
</Window>
 

sampleuse2.xml

<mycontrol:mycontrolBase
                         x:Class="My.Project.View"
                         ...
                         xmlns:converters1="clr-namespace:RQ.Windows.Converters"
                         ...>
    ...  
    <TextBlock Text="{Binding DataContext.ShowTaxApplicationTypes, Source={StaticResource Spy}, Converter={x:Static converters1:DatabindingDebugConverter.Instance}}" />
    ...  
</mycontrol:mycontrolBase>