Ngui Text Vertical Scrollbar?

Yeah, it turned out to be a bit of a pain in the ass to do this. I'm sure there are better ways to do it, but here's my solution (it scrolls a parent object with anything in it, it can be text or other stuff). Should be pretty easy to use and self-explanatory:

 using UnityEngine;
 using System.Collections;
 
 //=============================================================================
 // Manages the scrolling of the contents inside a clipped panel
 // Just put all objects to be scrolled inside a common parent, and then setup
 // the panel, the scrollbar, and the common parent object in the inspector.
 //
 // Make sure this script does not sit on the scrollbar gameobject itself, since
 // we will be disabling it when the scrollbar is not needed.
 //=============================================================================
 public class UIPanelScroller : MonoBehaviour {
     
     public UIScrollBar scrollBar;
     public UIPanel     clippingPanel;
     public Transform   panelContentsParent;
     
     public float checkContentsInterval = 0.1f;
     public bool  alwaysShowScroller = false;
     
     private float contentsZeroY;
     
     //========================================================================
     void Start () {
         this.scrollBar.onChange += this.OnScrollbarChange;
         
         this.scrollBar.scrollValue = 0;
         this.contentsZeroY = this.panelContentsParent.localPosition.y;
         
         this.UpdateStuff();
         this.StartCoroutine(this.CheckContentsChanges());
     }
 
     //========================================================================
     IEnumerator CheckContentsChanges()
     {
         while (this.enabled) {
             yield return new WaitForSeconds(this.checkContentsInterval);
             this.UpdateStuff();
         }
     }    
 
     //========================================================================
     private float _getContentsHeight() {
         float relative = NGUIMath.CalculateRelativeWidgetBounds(this.panelContentsParent.transform).size.y;
         return relative * this.panelContentsParent.transform.localScale.y;
     }
     
     //========================================================================
     void UpdateStuff()
     {
         float panelH   = this.clippingPanel.clipRange.w;
         float contentH = this._getContentsHeight();
         this.scrollBar.barSize = panelH / contentH;
         
         this.scrollBar.gameObject.SetActive(true);
         if (contentH < panelH && !this.alwaysShowScroller) {
             this.scrollBar.gameObject.SetActive(false);
         }
     }
     
     //========================================================================
     void OnScrollbarChange(UIScrollBar ignored)
     {
         float nonVisibleHeight = this._getContentsHeight() - this.clippingPanel.clipRange.w + this.clippingPanel.clipSoftness.y;
         float contentPos = this.contentsZeroY + (nonVisibleHeight * this.scrollBar.scrollValue);
         this.panelContentsParent.transform.SetLocalPosY(contentPos);
     }
     
 }

SetLocalPosY is a simple extension method I use to avoid having to make a copy of stuff everytime I want to change a single value:

 public static void SetLocalPosZ(this Transform trans, float z) {
     Vector3 vector = trans.localPosition;
     vector.z = z;
     trans.localPosition = vector;
 }

I had some issues with the clipping panel refusing to show it's contents at startup, because everything was cached up in NGUI, so I had to make this hack to shake things up:

 public class UIPanelClipRefreshHack : MonoBehaviour {
 
     public void GO() {
         foreach(UIWidget widget in this.GetComponentsInChildren<UIWidget>()) {
             widget.enabled = false;
             widget.enabled = true;
         }
     }
 }

Drop it on the panel, and call Go when displaying your window.

Phew!