I think this information about setting AutoCloseDelay = 0 should be on the demo page that David mentions. That page is dedicated to demonstrating and explaining the ToolTip "Hide on Event".
Without this information, it makes nearly all the statements on the page incorrect and you will have a lot of developers thinking the control has a bug.
For instance: Default - hides when mouse is out of the target element
This is not true. It's really - hides when mouse is out of the target element or after mouse has been inactive in the target element for 3 seconds.
Many of us want to leave the tip open, particularly if the tip may take longer than 3 seconds to read. So when we read this page, we assume we can achieve what is stated and we will not be able to guess that we have to set the AutoCloseDelay to 0.
I suggest putting this information above the Radio Buttons that allow the user to test the different hide events.