MouseUpCommand fires only sporadically - wpf

Question

I have created an attched property to bind the MouseUpCommand and the MouseDownCommand to my ViewModel. While the MouseDownCommand fires as it should, the MouseUpCommand only fires sporadically. Does anyone know what I am doing wrong?
Here is my XAML:
<ItemsControl ItemsSource="{Binding Page.Collection}" Grid.Row="1" Grid.Column="1"
HorizontalAlignment="Stretch" VerticalAlignment="Stretch">
<ItemsControl.ItemsPanel>
<ItemsPanelTemplate>
<Canvas IsItemsHost="True" Grid.Row="1" Grid.Column="1" HorizontalAlignment="Stretch" VerticalAlignment="Stretch"
Background="Blue"
local:MouseBehaviour.MouseUpCommand="{Binding ViewModel.MouseUpCommand}"
local:MouseBehaviour.MouseDownCommand="{Binding ViewModel.MouseDownCommand}"
local:MouseBehaviour.MouseMoveCommand="{Binding ViewModel.MouseMoveCommand}">
</Canvas>
Here is the MouseBehavior:
public class MouseBehaviour
{
#region MouseUp
public static readonly DependencyProperty MouseUpCommandProperty =
DependencyProperty.RegisterAttached("MouseUpCommand", typeof(ICommand), typeof(MouseBehaviour), new FrameworkPropertyMetadata(new PropertyChangedCallback(MouseUpCommandChanged)));
private static void MouseUpCommandChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
FrameworkElement element = (FrameworkElement)d;
element.PreviewMouseUp += element_MouseUp;
}
static void element_MouseUp(object sender, MouseButtonEventArgs e)
{
FrameworkElement element = (FrameworkElement)sender;
ICommand command = GetMouseUpCommand(element);
command.Execute(e);
}
public static void SetMouseUpCommand(UIElement element, ICommand value)
{
element.SetValue(MouseUpCommandProperty, value);
}
public static ICommand GetMouseUpCommand(UIElement element)
{
return (ICommand)element.GetValue(MouseUpCommandProperty);
}
#endregion
#region MouseDown
public static readonly DependencyProperty MouseDownCommandProperty =
DependencyProperty.RegisterAttached("MouseDownCommand", typeof(ICommand), typeof(MouseBehaviour), new FrameworkPropertyMetadata(new PropertyChangedCallback(MouseDownCommandChanged)));
private static void MouseDownCommandChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
FrameworkElement element = (FrameworkElement)d;
element.PreviewMouseDown += element_MouseDown;
}
static void element_MouseDown(object sender, MouseButtonEventArgs e)
{
FrameworkElement element = (FrameworkElement)sender;
ICommand command = GetMouseDownCommand(element);
command.Execute(e);
}
public static void SetMouseDownCommand(UIElement element, ICommand value)
{
element.SetValue(MouseDownCommandProperty, value);
}
public static ICommand GetMouseDownCommand(UIElement element)
{
return (ICommand)element.GetValue(MouseDownCommandProperty);
}
#endregion
}
I have tried using the normal mouse commands as well as the preview mouse commands. No difference.

Answer 1

If I break the MVVM pattern and just add events to the code behind the program works flawlessly:
private void ItemsControl_MouseUp(object sender, MouseButtonEventArgs e)
{
mainViewModel.ViewModel.MouseUp(e);
}
private void ItemsControl_MouseMove(object sender, MouseEventArgs e)
{
mainViewModel.ViewModel.MouseMove(e);
}
private void ItemsControl_MouseDown(object sender, MouseButtonEventArgs e)
{
mainViewModel.ViewModel.MouseDown(e);
}