In the model explorer you can turn on and off categories (i.e. buildings, trees) but you cannot turn off individual data sources (using the lightbulb tool in the Model Explorer). This seems like a simple fix and this function already exists with other Autodesk Software like Revit and AutoCAD so why not Infraworks? Especially since Infraworks is the ideal place to compile and view diverse data sources. It makes sense that you would want to turn them on and off on occasion.
This also helps when one data source has been imported but you are unsure if it is actually showing up in the 3D view.