Account for DPI scaling when positioning menu.

Author: grokys

src/GitHub.VisualStudio/UI/Views/PullRequestDetailView.xaml.cs

@@ -103,10 +103,13 @@ void DoOpenOnGitHub()
         void DoOpenChangesOptionsMenu(dynamic o)
         {
             var menu = changesSection.ContextMenu;
+            var g = System.Drawing.Graphics.FromHwnd(IntPtr.Zero);
+            var scaleX = g.DpiX / 96.0;
+            var scaleY = g.DpiY / 96.0;
             menu.DataContext = DataContext;
             menu.Placement = PlacementMode.Absolute;
-            menu.HorizontalOffset = o.MenuX;
-            menu.VerticalOffset = o.MenuY;
+            menu.HorizontalOffset = o.MenuX / scaleX;
+            menu.VerticalOffset = o.MenuY / scaleY;
             menu.IsOpen = true;
         }