Today, I noticed that ALL alert icons are missing from my map. I'm referring to the little "bell" shaped icon that indicates an alert has been set for a topic. However, the actual alerts themselves still appear to be defined. I can see them by accessing the "Manage Topic Alerts" menu. They just fail to appear as icons in the actual map itself. This is problematic because it's very important to me to be able to quickly see that I've set an alert for various topics.
I can't recall doing any action that would cause them to disappear from view. I tried examining various options under the "View" tab, but I didn't find any obvious solution.