Hi there! My name is***** would be my pleasure to help you with this. It sounds as though the Multi Window feature is turned on.
Please give this a try and let me know the results. If it solves the problem, would you mind taking a moment to rate my service? I'd really appreciate it! You can give your rating by selecting the stars located on the top right of the question page and then clicking on submit.
If this doesn't resolve your problem, please reply back and let me know whether your Samsung Galaxy Tab 4 is the 7" model or the 10" model. Thank you!
Thank you for that information. Please take a look at these illustrated instructions for the 7" model.
Please let me know if that helps you to turn off Multi Screen.