Occurs when any tooltip on the element is opened.
Assembly: PresentationFramework (in PresentationFramework.dll)
To manually open tooltips, handlers of the events should mark the relevant event as handled. Otherwise, the value of the ToolTip property will be used to automatically open a context menu. Marking the event handled will effectively cancel the default action, and could be an opportunity to reset the value of the ToolTip property and then open the new ContextMenu. Note that this event will not be raised if ToolTip is a null reference or otherwise unset.
This event cannot be an EventTrigger in a style. This is because the identifier field of this event re-uses an implementation from a service that does not expose add/remove methods on the event.
Available since 3.0