Returns the actual tooltip to display.
Original signature is '- (NSString *)textView:(NSTextView *)textView willDisplayToolTip:(NSString *)tooltip forCharacterAtIndex:(NSUInteger)characterIndex'
Available in Mac OS X v10.3 and later.

C# | Visual Basic | Visual C++ |
public delegate NSString TextViewWillDisplayToolTipForCharacterAtIndexEventHandler( NSTextView textView, NSString tooltip, NSUInteger characterIndex )
Public Delegate Function TextViewWillDisplayToolTipForCharacterAtIndexEventHandler ( _ textView As NSTextView, _ tooltip As NSString, _ characterIndex As NSUInteger _ ) As NSString
public delegate NSString^ TextViewWillDisplayToolTipForCharacterAtIndexEventHandler( NSTextView^ textView, NSString^ tooltip, NSUInteger characterIndex )

- textView (NSTextView)
- The text view sending the message.
- tooltip (NSString)
- The proposed tooltip to display.
- characterIndex (NSUInteger)
- The location in textView.

The actual tooltip to display, or nil to suppress display of the tooltip.

- Available in Monobjc Bridge: 10.6 (For Mac OS X 10.6 and later), 10.5 (For Mac OS X 10.5 and later)