Making a lagacy UI element always appear on top

I'm porting my game to win store and have a gameobject that persists between scenes and controls functionality for that platform, however it needs to display error messages if, for instance, cloud saves can't be accessed.
Is there any way to ensure that the error message appears over (in front of) any other (legacy) UI elements that might be displaying? I've tried the new UI system but it seems to always appear behind the legacy UI, I've also tried the legacy UI but that usually appears behind as well, I guess because it happens to get executed first.
Any suggestions appreciated!

 

Both GUI.Depth and GUI.ModalWindow can be used accomplish what you're after.

 

Thanks Naster, worked out a way to always get the error messages executing last, but if I still have any problems GUI.ModalWindow seems the perfect solution!