Expression Blend 3 Design Mode Exclamation Mark

I'm editing a ListViewItem template and I'm trying to add a custom control to the template but when I do I get a warning box surrounding my control that I add.

Here is the pic.

Notice the image isn't re-sizing that is part of the custom control.

Why is this happening to my control? I've used this control many times in my application with no problems re-sizing, etc., why the problems in 开发者_如何学Pythonthe template?

You just have to rebuild the application. Blend is telling you it's not sure what you're referring to.

UPDATE: On re-reading your post, now I'm not sure that a rebuild will work. I'll wait to see what rebuilding does (since that's always worked for me), then respond with further help.