RadToolTip for ASP.NET AJAX Version Q3 2008 released 11/25/2008 (release history)

RelativeTo property

Positioning a RadToolTip relative to the browser window (instead of to the mouse or to an element) is very useful in some scenarios. In this manner different styles can be built, for example an Outlook one, in which the tooltip is shown in the right bottom area of the browser.
This can be easily done by setting the RadToolTip's RelativeTo property to BrowserWindow and the Position property to the desired value.
A lot of configuration combinations are possible and it is important to know the following rules by which the tooltip determines how and when to be shown:

1. The default scenario is when the RadToolTip has its TargetControlID set and also has these settings: RelativeTo="Mouse" or MouseTrailing = "true". In this case its position is calculated according to the mouse coordinates.
2. The setting RelativeTo=BrowserWindow has a highest priority - the RadToolTip is shown relative to the browser, not to a target control even if a TargetControlID has been specified.
3. If the TargetControlID is not set and the ShowEvent is "FromCode" then the tooltip is positioned relative to the browser window. The OffsetX and OffsetY values are calculated using the browser corner (based on the Position property setting).
4. If the TargetControlID is set and the ShowEvent is "FromCode" the tooltip's position is calculated relative to the element.
5. If the tooltip has RelativeTo="Mouse" and TargetControl is set, and yet its showing is invoked programmatically from code the tooltip is positioned relative to the target element.
6. If the tooltip has RelativeTo="Element" and TargetControl is set, its position is calculated according to the specified element.