A problem that has cost me a good few hours in Visual Studio when programming a WPF application with C#

A problem that has cost me a good few hours in Visual Studio when programming a WPF application with C#
If you program using C# and store your data in an XML file, then it also happens very often that
UserControls are relatively practical due to their multiple usability. If you create more complex user controls in C#/XAML, e.g. with