Thanks for the reply.
Probably need to rephrase a bit. In the picture the NGUI camera is on the small collection of objects at the top, . The 'pink' rectangle seems to be positioned over the main camera (on different Layers) and the UIRoot dimensions (Flexible, min 1080, max 1536). Before upgrading this was overlaid the NGUI camera and seemed to use the game window size. Before the tiny button (top left of game scene) appeared the same as the 3 absolute positioned buttons (not using anchors).
It all works out correctly runtime, but makes things tricky when setting up the gui in design mode.
Camera is child of UIRoot, UI Root is positioned at 0,20. Pink rectangle seems centered on 0,0.
Any ideas?