Widgets always come in to viewport with a zorder of 0 after being removed and added back

If a widget is removed from parent and then gets added back to the screen later it will come in with a zorder of 0.

1. Open Editor
2. Create a new Widget Blueprint
   Right click content browser > User Interface > Widget blueprint
3. Open Widget blueprint
4. Add a button to the designer graph
5. Add an image to the designer graph
6. Make the Canvas panel a variable
   Click the Canvas panel > Top of the detail panel > Click the Is Variable check box
7. Create a click event for the button that was added
8. While in the event graph create the blueprint in the attached image
9. Compile save
10. Open the level blueprint
11. Add the New widget to the viewport
    Event begin play > Create widget > Add to viewport
12. Play In Editor
13. Click the button
14. Notice the image is removed and added (expected)
15. Open Widget Blueprint
16. Add another button at X=0, Y=0
17. Click PIE
18. Click the button that toggles the image
19. Notice now that the image is not showing up. This is because it is behind the second button.