I don't know what happened but suddenly my SharePoint 2013 ribbon disappeared. When I click Edit Page, it doesn't show me the ribbon.
To get the ribbon back, click the Settings wheel then click Show Ribbon.
I had created a Register site based on the Site Contents App "Lists". I wanted a subheading and created one using the web part. The ribbon bar disappeared from my views. To ensure this doesn't happen, before adding a new web part you need to create another view, so that you have "All Items" and something else. In the "All Items" view, create your new web part. The ribbon bar will disappear, but your second view will have it available for use. Not sure of another way of doing this. JR