Editing the System View of My Dashboard is counter-intuitive. By edit, I mean add widgets.
There two ways to view My Dashboard, but only one of those ways will allow you to edit the System View of My Dashboard.
1. Expand Dashboards in the side menu
2. Select My Dashboard
Now to edit the dashboard you would expect to choose Edit for Actions, but this will not let you change what is on the system view.
1. Select Dashboards in the side menu. Do not expand it. Just select Dashboards.
2. This gives you a list of dashboards in the system.
3. Find My Dashboard and click edit. This does not give an option to edit the widgets on System View.
4. Instead, select My Dashboard to view in the light box.
Now, you have the options (if an administrator) to add widgets to the System View.
Make both ways of viewing My Dashboard the same. View it from the side menu should allow you to add widgets to the System View.
Add System View | Private View to the side view My Dashboard