I recently tried to make a time-enabled map. I made sure the temporal data worked in ArcMap 10. I exported the data into a .zip and uploaded it to my map on arcgis.com There isn't much help under the help topics for creating time enabled maps, but what I could find said I needed to go to the time-enabled layer on arcgis.com and click on description. However, description is grayed out and unavailable. Did I miss a step? None of the other layers I have uploaded have description as an available option either. How do I enable the layer description?