We could surely benefit from the incorporation of legend property options in the online ArcGIS. I asked if it was possible to configure the visible features (example: limit the number of map notes being shown) in a question post, and got this reply. Would be great to be able to limit the symbols, etc that are shown to ones that are used in the current map extent. That'd really clean up presentations that students make, and simplify the look of a map or presentation.