✅ Choosing the right Event in WPF

I have created a notification marker that you can see on the image. It shall display how many new entries are within a DataGrid in a wpf app. Entries are new when they haven't been noticed by the user. Now the question is what Event do I use for the user to notice the entries? I thought about using click event on the Missed Calls textblock as a way to say "I've noticed those 19 missed Calls" in the MissedCalls DataGrid. But apparently TextBlock doesn't have a Click event, what other event could I use for this?