wpf - Odd Loaded behavior in markup versus code -

I am currently very confused with the different behavior about the FrameworkElement.Loaded event. There is a small example app that shows it.

Xaml:

  & lt; Window x: orbit = "wpfApplication1.Window1" xmlns = "http: /sschems.microsoft.com/winfx/2006/xaml/presentation" xmlns: x = "http://schemas.microsoft.com/winfx/2006/ Xaml "title =" window 1 "height =" 300 "width =" 300 "loaded =" window_loaded "& gt; & Lt; Grid & gt; & Lt; TabControl & gt; & Lt; TabItem Header = "Tab 1" / & gt; & Lt; TabItem Header = "Tab2" & gt; & Lt; WindowsFormsHost name = "formhost" loaded = "form host_loaded" /> & Lt; / TabItem & gt; & Lt; / TabControl & gt; & Lt; / Grid & gt; & Lt; / Window & gt;  

Code:

  using System.Windows; Namespace WpfApplication1 {Public partial squares window 1: window {public window 1 () {InitializeComponent (); } Private Zero Window_loaded (Object Sender, Routing Avenger EG E) {formHost.Loaded + = delegate {MessageBox.Show ("Representative"); }; } Private Zero formhost_loaded (Object Sender, Routing Avenger AGE E) {Message Box. Show ("markup"); }}}  

As soon as I run the application, I get two instant messagebox es - "markup" and "representative". If, however, I delete Loaded = "formHost_Loaded" to WindowsFormsHost , I do not get it at startup, it clearly shows that I have a "markup" dialog Why not get it, but why does it remove "representative"? I think that in its sequence, the events that are called (window versus their children) have to do this, but I find it difficult to find out.

Note: You can replace WindowsFormsHost with other controls, it should not really make any difference - I was just using it for some more tests.