Theming
Telerik themes are not turned on by default in RadToolTip. In order to use the predefined Telerik styles you can define a ContentTemplate for the RadToolTip component and use the RadToolTipContentView control inside the template.
The following code example demonstrates how to set up RadToolTip to use the Telerik themes.
Example 1: Setting ToolTipContentTemplate property
Example 2: Setting ToolTipContent property
The end result is demonstrated in the picture below: