NGUI ScrollView

Organize game-objects as seen in the Hierarchy Tab below.

All background goes into Panel-Window.

All scrollable items goes into Panel ClipView.

Attach UIGrid.cs to UIGrid (Component -> NGUI -> Interaction -> Grid)

Set Clipping in Panel ClipView and attach UIDraggable Panel.cs to it (Component -> NGUI -> Interaction -> Draggable Panel)

Attach BoxCollider and UIDraggable Panel Content.cs to Outline (Panel-Window)