Data disappearing from pop-up in backend

I’m having a lot of troubles with your plugin. When adding data in the text field in the custom tab pop-up box I click done, it saves but then if I go back in to try to adjust something the box is blank, like the data totally disappeared. Also sometimes if I toggle between text and visual some of the data gets lost.

Before that I was having some formatting issues but I seemed to figure out a good work around for that.