Should I remove the references to System.Windows.Controls.DataVisualization.Toolkit from my application ifI'm using the Infragistics stuff?
There's no reason you need to remove it if you still find some of its classes useful. Just be aware that there could very well be namespace conflicts between the assemblies so you may need to specify a full namespace path here and there. If you aren't using any classes in that assembly any further then, by all means, remove it.
-Graham