WinForms/WPF Interop ElementHost Not Drawing The WPF Control!

<Edit>

It turns out it wasn’t externalizing the WPF control that solved the issue, but rather changing my build configuration to Release instead of Debug.  When I added the externalized assembly, I set the configuration to Release.  I’m not sure exactly why a debug build would cause this behavior…

</Edit>

<Edit 2>

It seems to work properly on Windows XP regardless of the build configuration.  Might be a Windows 7 thing…

</Edit 2>

I’ve been doing a lot of WPF work lately and a lot of it has been with WinForms interoperating with WPF.  Today I noticed some odd behavior when I tried to add a WPF control to a WinForms ElementHost object…

Usually I put the WPF control in a separate assembly, but today I thought I didn’t need to since it was just a very simple control.  Immediately I saw that the WPF control wouldn’t draw itself properly for some reason.  It would only draw itself sometimes, but if i clicked on the WPF control and somehow hit a Button or ComboBox, the control would show up.

I then decided to try and put the simple control in its own assembly and that solved the problem… It looks like there’s some issues with including a WPF control in a WinForms project directly, in my case anyway.  I’m using Visual Studio 2008 on Win7 x86 and if anybody else has this type of issue, try doing what I did to resolve the issue.