RadTooltipManager uses an UpdatePanel to perform AJAX calls to the server.
The UpdatePanel is created and initialized in the OnInit
event of the RadTooltipManager - e.g. relatively early in the (overall) page lifecycle.
The early creation is needed so that the UpdatePanel is able to have its content populated - and allow for any contained elements such as buttons etc. to be properly initialized and execute their own event handlers.
Thus, the earlier in the page lifecycle you create the RadTooltipManager - the better.
In case you encounter specific issues and errors, please let us know in more detail or open a support ticket and send us your code. We will examine it and get back to you with a suggestion how to proceed.
All the best,
the Telerik team