public virtual bool IsMultiline(TextDocument document)
{
if (document == null)
throw new ArgumentNullException("document");
ISegment surroundingSegment = this.SurroundingSegment;
if (surroundingSegment == null)
return false;
int start = surroundingSegment.Offset;
int end = start + surroundingSegment.Length;
return document.GetLineByOffset(start) != document.GetLineByOffset(end);
}