Please note that if you have set the targetControlID property of each tooltip and their ShowEvent is different than FromCode they will automatically attach the needed events to their target elements.
if that is not the case I would suggest adding the desired controls in the targetControlID property of the tooltip when you create it (I assume you do so from the code-behind). You could also use the RadToolTIpManager and add all the desired targets to its targetControls collection. You could also use the autotooltipify functionality of the manager, depending on the scenario.
Please examine the following list of online demos to see some useful ideas on using tooltips:
All the best,
the Telerik team
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