Hello,
I've found a bug.

Steps to reproduce

1. Open documentation, Getting started section, WPF (XAML) chapter
2. Follow steps in "Create the view" part regarding how to add Plot control at Toolbox
3. Browse OxyPlot.Wpf.dll in solution folder and add it to Toolbox

Platform: Windows 10, Visual Studio 16.4.1
.NET version: Core 3.0
OxyPlot version: OxyPlot.Wpf 2.0.0

Expected behaviour

Plot control added at Toolbox so it could be used in design view.

Actual behaviour

Following error message appears:

I tried different versions of this dll from neighbour subfolders in "packages" folder - none helped.