Board Thread:Support Requests - Getting Technical/@comment-25029082-20170311182844/@comment-9605025-20170311192759

I used to be confused by this as well. The reason is that the caption is actually treated the same as "alt=". This takes the text and uses it for the HTML alt attribute. How the data in the alt attribute is displayed depends on the browser. Some browsers display it as hover text, which is what you want. However, other browsers display the contents only when the image cannot be rendered.