The AutoCloseDelay property is not obsolete and my colleagues has not stated this. As for the other two - setting them to false is not necessary - the default behavior of the RadToolTip is to hide when the mouse leaves the target element and it does not display a close button. To display a close button you need to explicitly set the HideEvent to ManualClose, so if you have not done this you will not have the [X] button. On the Sticky property - its modern equivalent is explicitly setting the HideEvent to LeaveToolTip. Therefore I advise that you do not set these two obsolete properties at all, as advised in the post you linked.I hope this clears things for you.
the Telerik team
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