Yes, this is done on purpose. While discussing the different situations in which our control should be used, we came up with the following one:
- you want to "tooltipify" an element;
- before the RadToolTip opens, you want to dynamically add an ASP Button in it;
- additionally, you want to use th Click event of that button;
This situation requires that the AjaxUpdate event fires before any other event in order to ensure the Button is created early enough in the page lifecycle, so that the Click event could fire.
Having this particular situation in mind, our developers decided, that the best approach would be to fire the AjaxUpdate event before the Page_Load.
I hope I was able to explain why we have decided to implement the AjaxUpdate event this way.
All the best,
the Telerik team