Hello Jim,
Please refer to the attached sample implementing the above code which works correctly at my end using the latest C1Chart Build : 2/4.0.20133.24028 available at :
prerelease.componentone.com/dotnet20/C1Chart/2013-T3/C1Chart.2_2.0.20133.24028.zip
prerelease.componentone.com/dotnet40/C1Chart/2013-T3/C1Chart.4_4.0.20133.24028.zip
If the issue persists with the latest build too then I would request you to share a stripped down sample of your code replicating the issue or make the necessary changes to this sample so that I could debug the issue at my end and provide you with appropriate assistance.
Regards,
Reema