With TextFormattingMode.Display VisualLine bottom bound not recognized. As result mouse cursor changing and selection below control buggy.

Author: Reshetnikov_AS

ICSharpCode.AvalonEdit/Editing/SelectionMouseHandler.cs

@@ -531,7 +531,7 @@ int GetOffsetFromMousePosition(Point positionRelativeToTextView, out int visualC
 			if (pos.Y > textView.ActualHeight)
 				pos.Y = textView.ActualHeight;
 			pos += textView.ScrollOffset;
-			if (pos.Y > textView.DocumentHeight)
+			if (pos.Y >= textView.DocumentHeight)
 				pos.Y = textView.DocumentHeight - ExtensionMethods.Epsilon;
 			VisualLine line = textView.GetVisualLineFromVisualTop(pos.Y);
 			if (line != null) {
@@ -552,7 +552,7 @@ int GetOffsetFromMousePositionFirstTextLineOnly(Point positionRelativeToTextView
 			if (pos.Y > textView.ActualHeight)
 				pos.Y = textView.ActualHeight;
 			pos += textView.ScrollOffset;
-			if (pos.Y > textView.DocumentHeight)
+			if (pos.Y >= textView.DocumentHeight)
 				pos.Y = textView.DocumentHeight - ExtensionMethods.Epsilon;
 			VisualLine line = textView.GetVisualLineFromVisualTop(pos.Y);
 			if (line != null) {