Steps to reproduce :

- create a new project in 4.6
- create a few buttons
- add an empty game object with the Grid Layout component and parent the buttons to it
- change the text of the buttons to be recognizable (e.g. A, B, C etc.)
- upgrade the project to 5.0 and notice that the order inside the layout is lost

*Note :
Can also be reproduced by upgrading the Layout scene in the example project.