I had a problem with a blank Visual tab. Turns out something was including everything that was supposed to be visible within an HTML script. On the Text tab, once I moved the close script (</script>)up ABOVE whatever should be visible on the Visual Tab, it was! For me, it was a TinyMCE script. Of course! Anything that’s written within a script field is not going to show on the Visual Tab.
Go to your Text Tab, find the close script HTML (</script>) that’s below what should be visible, select and cut that, find the script field above that which starts with (<script>), find the end of that, past the close script HTML where it’s supposed to be, and check you Visual Tab.
