Oxyplot plot not displaying in Prism module loaded by Unity

I have a line series plot in a WPF user control in a dll project that gets loaded by the main WPF application via unity. It's a pretty straightforward MVVM setup using Prism. The problem is when the program is run the oxyplot plot doesn't show up. I've tested to make sure the user control itself is loading, I replaced the plot with a built in textblock and that appeared. When viewing the user control in the designer the plot also shows up. It's only when the application is actually running that the plot does not appear. No exceptions are thrown and I don't see any errors so I don't know why the plot isn't being displayed.