Assembly: PresentationFramework (in PresentationFramework.dll)
XMLNS for XAML: http://schemas.microsoft.com/winfx/2006/xaml/presentation, http://schemas.microsoft.com/netfx/2007/xaml/presentation
Occurs when is set to false when a tooltip is not open.
A value of false for the property is not supported for a ToolTip when it is not open. To create a tooltip that stays open until the mouse button is pressed when it is outside the tooltip, you must set both the property and the IsOpen property to true. If is set to false when the tooltip is not open, a NotSupportedException occurs.