Trying out OxyPlot, installed and referenced packages. Copying and pasting the example from here <http://docs.oxyplot.org/en/latest/getting-started/hello-windows-forms.html> but it doesn't recognize `plot1` from the last line. I am guessing because the control isn't added to the form. How do I add it? I don't see it in the toolbox, and I tried adding the control to the toolbox and can't find it anywhere. Thanks.