I read that someone else had this issue.
I have this same issue on a sporting website I develop for. It is not the themes and no issues with other plugins. Basically when you use the plugin The Visual Editor in Posts and pages disappears.
All you see is the Add Media button and everything else is missing... The kitchen sink, the content, etc are all gone.
You basically have to turn off the plugin and paste the code from the website to use the poll on a page.