Last week, I actively engaged in answering newsgroups posts for Blend. Here are some features not supported for authroing in V1. However, if you create it manually by editing xaml yourself and then load the project in Blend, Blend should be able to handle it just fine. If it crashes, then please let us know and we will try to fix it before RTM.

• NavigationWindow: We ran into workflow related issues and decided not to support this for V1. If you want to create a NavigationWindow in your project:

To create a NavigationWindow. In an empty xaml file, paste the following and
point the source to whichever xaml you want in your project, in the example
below it is pointing to Page1.xaml.
<NavigationWindow
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="NavigationWindow Sample"
    Source="Page1.xaml" />

 Another simpler way to convert a Window to NavigatinWindow, is to replace the <Window> tags with <NavigationWindow> and wrap the child element of Window with <NavigationWindow.Content> tags.

• HierarchicalDataTemplate: Blend should be able to load any hand-created hierarchicaldatatemplates. But you cannot author them for V1. You will have to author them in xaml.

• XBAP and Deployment: We tried doing this, but decided to scale back for V1 as we ran into a bunch of implementation and workflow issues.

• Code Editng: Here too, we decided to scale back. Given the time we had for V1, we could not put in a code editor that was rich, powerful and well integrated with the rest of our tool. But we did get in good amount of Visual stuido interop code. So, folks can seamlessly modify code with VS and Blend will be able to pick up the changes. To edit code files, just right click on the project item and choose 'edit externally', this will open up VS with the code file. I usually prefer to do an 'edit externally' on the solution itself so that it opens the entire solution in VS instead of just the particular code file.

• DataGrid:Blend only supports what is in WPF and unfortunately, there is no DataGrid in WPF. You could implement your own datagrid using ListView. But if you are really bent on using a datagrid, then you can use "crossbow" to use winforms datagrid inside your wpf app. Here is a post that shows you how:http://geekswithblogs.net/lorint/archive/2006/09/09/90740.aspx