Merge pull request #2074 from Sorien/edit-box-selection

make sure pointer is always inside presenter

src/Avalonia.Controls/TextBox.cs

@@ -14,6 +14,7 @@ using Avalonia.Interactivity;
 using Avalonia.Media;
 using Avalonia.Metadata;
 using Avalonia.Data;
+using Avalonia.Utilities;
 
 namespace Avalonia.Controls
 {
@@ -655,6 +656,8 @@ namespace Avalonia.Controls
             if (_presenter != null && e.Device.Captured == _presenter)
             {
                 var point = e.GetPosition(_presenter);
+
+                point = new Point(MathUtilities.Clamp(point.X, 0, _presenter.Bounds.Width - 1), MathUtilities.Clamp(point.Y, 0, _presenter.Bounds.Height - 1));
                 CaretIndex = SelectionEnd = _presenter.GetCaretIndex(point);
             }
         }

src/Skia/Avalonia.Skia/FormattedTextImpl.cs

@@ -121,7 +121,7 @@ namespace Avalonia.Skia
 
                 int offset = 0;
 
-                if (point.X >= (rects[line.Start].X + line.Width) / 2 && line.Length > 0)
+                if (point.X >= (rects[line.Start].X + line.Width) && line.Length > 0)
                 {
                     offset = line.TextLength > line.Length ?
                                     line.Length : (line.Length - 1);