OnInspectorGUI Custom Drawing?

Questions & Answers
1

I’m trying to do custom drawing in the inspector or editor window but am not having much luck. I found the following conversation and have tried implementing this as a starting point, but my inspector view is either turning completely white or rendering garbage.
http://forum.unity3d.com/threads/134400-How-do-I-draw-in-the-inspector

Here’s my javascript version of the code:

class MyScriptEditor extends Editor {
	public var preview : RenderTexture = null;

	function OnInspectorGUI() {
		if(!preview) {
			preview = RenderTexture(256.0, 256.0, 24, RenderTextureFormat.ARGB32);
			preview.Create();
		}
		
		var newPreview : boolean = false;
		if(Event.current.type == EventType.MouseDown && Event.current.button == 0) {
			Debug.Log("Render");
			Graphics.SetRenderTarget(preview);
			
			GL.PushMatrix();
			GL.LoadOrtho();
			GL.Clear(true, true, Color(0,0,0,0));
			GL.Color(Color.red);
			GL.Begin(GL.LINES);
			GL.Vertex3(0.0, 0.0, 0.0);
			GL.Vertex3(100.0, 100.0, 0.0);
			GL.Vertex3(0.0, 100.0, 0.0);
			GL.End();
			GL.PopMatrix();
			
			newPreview = true;
		}
		GUI.DrawTexture(GUILayoutUtility.GetRect(64.0, 64.0), preview);
		
		if(newPreview) Repaint();
	}
}
2

The render target needs to get reset.