This is an example of how you can make a dialog box with "ok" and "cancel" buttons with a single sprite. Drag the sprite to your backpack and you can use in your own project. Change the text and colors as needed. Broadcast "show dialog" to make it popup. You can also build on the dialog to make other controls within the dialog.
I used the concept for dialog boxes in my Coinstar project: http://scratch.mit.edu/projects/34388198/ Feel free to use it in your own projects.
