I just installed the hotfix and the problem still exists.  It's about one in five tries of clicking the + - and holding the + down actually as soon as it appears (looks like don't need to keep clicking, just click the + and hold it down) - it'll either happen or it won't after a couple seconds.  This program below, after quick running, then clicking on the + and holding down I get object reference not found.

(all InitializeComponent has is the generic chart added which is a line chart) 

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;

using Infragistics.UltraChart.Data.Series;

using Infragistics.UltraChart.Data;

using Infragistics.UltraChart.Resources.Appearance;

using Infragistics.UltraChart.Shared.Styles;

public partial class Form1 : Form

this.ultraChart1.LineChart.TreatDateTimeAsString = false;

series = new NumericTimeSeries();

Timer timer = new Timer();

Sorry, still not getting the exception (using 8.2 build 2022, which is the latest hotfix build). This time i'm adding 100 points on every tick, all within 100ms. The only thing that happens when you click the scrollscale is the visible window coordinates change and the chart repaints Perhaps you can create a sample project and post it here. That might help reproduce the problem.

That looks like similar to mine, except when the timer ticks, add about 50-100 points, also you are adding days to your datetime, my points are about 100 ms apart, and my Y axis values are about 0.0000003 +- a .0000001.  It happens almost every time, when I first open the form, and then quickly click the + a couple times on the scrollscale.  Is there any part of the code on clicking that has some kind of timing involved?  I assure you it's happening on version 8.2 (latest)  Infragistics.   I appreciate all the help, this is a serious crippling problem for me!

NumericTimeSeries series;

void timer_Tick(object sender, EventArgs e)
{
   Random r = new Random();
   series.Points.Add(new NumericTimeDataPoint(DateTime.Now.AddDays(r.Next(500)), r.Next(500), "point", false));
}

This is a line chart on the latest Infragistics (8.2 .net 2.0).  I would say I have about 500 points or so when I first start, that I use a NumericTimeDataSeries to bind to and add to the graph's series, and also I add points dynamically about every second to that list.  The treatdatetimeasstring is = false (so I get time on the xaxis).  The scrollscale is enabled on both the x and y axis, however the error comes when I click the + sign on the xaxis scrollscale (not tried y axis one).  The x axis is set to auto (so it shows labels automatically given Infragistics ranges).  It usually occurs when I first bring the form up, and I quickly click the + a couple times.  It exceptions pretty consistently, every couple times or so, so it should be reproducible. 

 Thanks!  I really need this one fixed for sure.