diff --git a/ICSharpCode.AvalonEdit/Rendering/BackgroundGeometryBuilder.cs b/ICSharpCode.AvalonEdit/Rendering/BackgroundGeometryBuilder.cs
index 94015c17..cdd4c963 100644
--- a/ICSharpCode.AvalonEdit/Rendering/BackgroundGeometryBuilder.cs
+++ b/ICSharpCode.AvalonEdit/Rendering/BackgroundGeometryBuilder.cs
@@ -261,6 +261,9 @@ static IEnumerable<Rect> ProcessTextLines(TextView textView, VisualLine visualLi
 					} else {
 						right = visualLine.GetTextLineVisualXPosition(lastTextLine, segmentEndVC);
 					}
+
+					left -= scrollOffset.X;
+					right -= scrollOffset.X;
 					Rect extendSelection = new Rect(Math.Min(left, right), y, Math.Abs(right - left), line.Height);
 					if (!lastRect.IsEmpty) {
 						if (extendSelection.IntersectsWith(lastRect)) {