I have already replied to the support ticket opened by you on the matter so I paste my answer below:
I am sorry to say that intelligent labels functionality is not supported by RadHtmlChart. Such a feature request, however, has already been logged here, so that you can monitor, comment and raise its priority by voting on it.
For the time being I can suggest the following steps:
- Try to set a different position for the labels of each series:
- Or implement your own logic for offsetting the labels as illustrated in the feedback item.