Drift when restoring window location and size in WPF

Question

I am using the code below to save and restore the window position and size upon restart.

I am observing an upward drift of 28 pixels everytime I execute this code!

Am I reading the wrong values, or am I restoring them incorrectly? Where is the number 28 (size of the chrome?) coming from (and how would I account for it programmatically, rather than a fixed number in code)?

Here is my code:

public partial class MainStudioWindowControl : RibbonWindow
{
    public MainStudioWindowControl()
    {
        App.MainWindowOwner = this;
        this.Loaded += new System.Windows.RoutedEventHandler(MainStudioWindowControl_Loaded);
    }

    void MainStudioWindowControl_Loaded(object sender, System.Windows.RoutedEventArgs e)
    {
        System.Windows.Window mainWindow = System.Windows.Application.Current.MainWindow;
        mainWindow.WindowStartupLocation = System.Windows.WindowStartupLocation.Manual;
        if (Studio.Properties.Settings.Default.Width > 0)
        {
            mainWindow.Left = Studio.Properties.Settings.Default.Left;
            mainWindow.Top = Studio.Properties.Settings.Default.Top;
            mainWindow.Width = Studio.Properties.Settings.Default.Width;
            mainWindow.Height = Studio.Properties.Settings.Default.Height;
        }
        Debug.WriteLine(string.Format("Loading: Top = {0}", this.Top));
    }

    protected override void OnClosing(System.ComponentModel.CancelEventArgs e)
    {
        base.OnClosing(e);
        System.Windows.Window mainWindow = System.Windows.Application.Current.MainWindow;
        Studio.Properties.Settings.Default.Left = mainWindow.Left;
        Studio.Properties.Settings.Default.Top = mainWindow.Top;
        Studio.Properties.Settings.Default.Width = mainWindow.Width;
        Studio.Properties.Settings.Default.Height = mainWindow.Height;
        Studio.Properties.Settings.Default.Save();
        Debug.WriteLine(string.Format("Saving: Settings.Top = {0}", Studio.Properties.Settings.Default.Top));
    }
}

Answer 1

Try this:

1) Derive your class from the normal Window, not the RibbonWindow - if that fixes it, it's a RibbonWindow issue.

2) Use hard-coded values to set the measurments in the Loaded handler - if that fixes it, the problem's got something to do with the settings.

With these two changes, it worked fine for me. The window appeared where it should every time.