diff --git a/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Input/Stylus/Wisp/PenContexts.cs b/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Input/Stylus/Wisp/PenContexts.cs
index aa1ed22602c..7056049ace1 100644
--- a/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Input/Stylus/Wisp/PenContexts.cs
+++ b/src/Microsoft.DotNet.Wpf/src/PresentationCore/System/Windows/Input/Stylus/Wisp/PenContexts.cs
@@ -1,4 +1,4 @@
-// Licensed to the .NET Foundation under one or more agreements.
+// Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
 using System.Windows.Input.StylusWisp;
@@ -488,7 +488,7 @@ internal StylusPlugInCollection TargetPlugInCollection(RawStylusInputReport inpu
                 ptTablet *= stylusDevice.TabletDevice.TabletDeviceImpl.TabletToScreen;
                 ptTablet.X = (int)Math.Round(ptTablet.X); // Make sure we snap to whole window pixels.
                 ptTablet.Y = (int)Math.Round(ptTablet.Y);
-                ptTablet = _stylusLogic.MeasureUnitsFromDeviceUnits(stylusDevice.CriticalActiveSource, ptTablet); // change to measured units now.
+                ptTablet = _stylusLogic.MeasureUnitsFromDeviceUnits(inputReport.InputSource ?? stylusDevice.CriticalActiveSource, ptTablet); // change to measured units now.
 
                 pic = HittestPlugInCollection(ptTablet); // Use cached rectangles for UIElements.
             }