Can't seem to correctly add Helix Toolkit to my C# (Visual Studio Express 2012) project

Question

I've been trying to add a HelixViewport3D to my WPF application and keep failing spectacularly - I have managed to add references to some precompiled .dll's for .NET-4.5 from here , but then I still cannot add the desired element to the GUI.

Here's a screenshot which hopefully says everything you need to know:

After dragging the HelixToolkit.Wpf.dll file into the toolbox, and then trying to add it from there, this is what happens: to which no amount of "OK"-ing, restarting, or furiously mashing the keyboard will fix the problem

Answer 1

Unblock the zip file you downloaded before adding a reference to the dll. The VS designer fails due to the security restrictions added to files downloaded from the internet.