Drag and Drop Interaction - How to make learners finish before submitting

For the purposes of troubleshooting, I made a couple of changes to your file. I removed some of the cards so I could just test to make sure the mechanics were working as expected. I also added checkmarks to the drag correct states so I could verify that the states were changing. 

You had setup the triggers to change the states and the conditions on the Done button correctly! There just wasn’t anything in the file to show that the Done button was doing its thing, so I added a results slide and a trigger to go to it so I could make sure the Done button was submitting properly. I had to make some changes in the Question properties to make that work. 

Going back to your original question of preventing folks from submitting too soon, I added a trigger to disable the done button when the slide starts (and changed the color on the disabled state to grey so I could make sure it was working). I tried setting it up that the Done button would change to enabled when the states of the objects were all correct but that was messy and not working for me. I switched it to the Done button became enabled once the last object was moved over. 

Hope that helps!