Thanks ArenMook and dipu5683!
I found the problem ( not the solution
)
I have three cameras in the scene. Camera1 and Camera2 are Clear Flags=Depth Only so that their view can be overlapped on Camera3 :
Camera 1 : Camera that is created by NGUI (when I created first sprite) and this sees all the 3d-GUI. I have 3d-objects and sprites for GUI.
Camera 2 : Camera that sees the game-play element which in this case is draggable object.
Camera 3 : Back camera that sees background-image.
Camera 1 sees a big button that covers the complete screen when you click on that button, it disables Camera1 and enables Camera2 so that you can start playing the game.
Problem : Problem is that even when I disable Camera1 (NGUI camera) and switch to Camera2. Camera1 still raycasts on big-button that covers the draggable object and that is why it never picks draggable object ( which I am able to see in Camera1-Debug )
NGUI camera raycasts on the elements that are visible to it evenwhen it is disabled which blocks the click-detection on other elements visible by another camera
I appreciate your help!
Thanks