Course not working properly

I may not have fully gotten what you are trying to do but one thing to double-check is that you don't have any auto-advance slides that are moving things along. The other thing you might consider to try is that a trigger changes the submit button from hidden to normal when the user clicks into the submit box. You might also add an if condition to the submit button that it only submits or goes back if the text box contains text. Good practice here would be to have a popup say why the button didn't work and remind the user to enter in text. Using javascript in the trigger you could even get the text value and determine the length if you require a certain length of answer. 

Sometimes with trigger logic like this you can also try setting up a variable like "submitting". Then when the button is pressed you can change this variable. Then you can set other triggers to happen when a variable changes.