I already answered your support thread and for your convenience and for others who might have teh same question I pasted it below:
Basically, when you use a RadToolTip in SharePoint you should configure it in the same manner and logic as outside the SharePoint environment. In specific scenarios and settings, you might encounter a positioning problem due to using quirks mode (this is the main difference in a SharePoint scenario) but as far as I understand you have not encounter such an issue but you have not tooltipified the records yet.
What I can suggest is the following:
1) First, determine whether separate RadToolTips or a RadToolTipManager suits better your scenario - more about the differences in usage is available below:
2) After you have decided what exactly you want to use, examine the particular online demos which show how to set the target controls and how to populate teh content. The demos are available here:
3) After you have gone through the steps above, the tooltips with the relevant information should start showing with teh same code, no matter you use SharePoint or not.
If you encounter a problem either with the steps above or with specific behavior after you have already the tooltips showing, please provide more details, e.g what kind of list you are using, etc or best - prepare a simple, fully runnable reproduction demo based on your code with a standard ASP.NET WebSite which is without a DOCTYPE declaration and teh content is in a WebUserControl - this should simulate teh SharePoint scenario and once I receive it along with your explanations, I will modify it according to your requirements and you will then be able to apply the same logic in your original application.
I hope that my reply is helpful, let me know how it goes.
All the best,
the Telerik team
Do you want to have your say when we set our development plans? Do you want to know when a feature you care about is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items