diff --git a/src/BizHawk.Bizware.Input/KeyMouseInput/X11KeyMouseInput.cs b/src/BizHawk.Bizware.Input/KeyMouseInput/X11KeyMouseInput.cs
index b714827e4c..3b12eed679 100644
--- a/src/BizHawk.Bizware.Input/KeyMouseInput/X11KeyMouseInput.cs
+++ b/src/BizHawk.Bizware.Input/KeyMouseInput/X11KeyMouseInput.cs
@@ -184,19 +184,10 @@ namespace BizHawk.Bizware.Input
 							{
 								var rawValueIndex = 0;
 
-								// not implemented until netcore / netstandard2.1
-								// copied from modern runtime
-								static bool IsNormal(double d)
-								{
-									var bits = BitConverter.DoubleToInt64Bits(d);
-									bits &= 0x7FFF_FFFF_FFFF_FFFF;
-									return (bits < 0x7FF0_0000_0000_0000) && (bits != 0) && ((bits & 0x7FF0_0000_0000_0000) == 0);
-								}
-
 								if (XIMaskIsSet(valuatorsMask, 0))
 								{
 									var deltaX = xiRawEvent->raw_values[rawValueIndex];
-									if (IsNormal(deltaX))
+									if (!double.IsInfinity(deltaX) && !double.IsNaN(deltaX))
 									{
 										mouseDeltaX += deltaX;
 									}
@@ -207,7 +198,7 @@ namespace BizHawk.Bizware.Input
 								if (XIMaskIsSet(valuatorsMask, 1))
 								{
 									var deltaY = xiRawEvent->raw_values[rawValueIndex];
-									if (IsNormal(deltaY))
+									if (!double.IsInfinity(deltaY) && !double.IsNaN(deltaY))
 									{
 										mouseDeltaY += deltaY;
 									}
diff --git a/src/BizHawk.Client.EmuHawk/MainForm.cs b/src/BizHawk.Client.EmuHawk/MainForm.cs
index f4c2f8eb78..c394172d7c 100644
--- a/src/BizHawk.Client.EmuHawk/MainForm.cs
+++ b/src/BizHawk.Client.EmuHawk/MainForm.cs
@@ -4899,23 +4899,27 @@ namespace BizHawk.Client.EmuHawk
 						fbLocation.Offset(_presentationPanel.Control.Location);
 						var barrierRect = new Rectangle(fbLocation, _presentationPanel.Control.Size);
 
-						// each line of the barrier rect must be a separate barrier object 
+						// each line of the barrier rect must be a separate barrier object
+						// also, the lines should span the entire screen, to avoid the cursor escaping at the corner
+
+						var mfScreen = Screen.FromControl(this);
+						var screenRect = mfScreen.Bounds;
 
 						// left barrier
 						_pointerBarriers[0] = XfixesImports.XFixesCreatePointerBarrier(
-							_x11Display, Handle, barrierRect.X, barrierRect.Y, barrierRect.X, barrierRect.Bottom,
+							_x11Display, Handle, barrierRect.X, screenRect.Y, barrierRect.X, screenRect.Bottom,
 							XfixesImports.BarrierDirection.BarrierPositiveX, 0, IntPtr.Zero);
 						// top barrier
 						_pointerBarriers[1] = XfixesImports.XFixesCreatePointerBarrier(
-							_x11Display, Handle, barrierRect.X, barrierRect.Y, barrierRect.Right, barrierRect.Y,
+							_x11Display, Handle, screenRect.X, barrierRect.Y, screenRect.Right, barrierRect.Y,
 							XfixesImports.BarrierDirection.BarrierPositiveY, 0, IntPtr.Zero);
 						// right barrier
 						_pointerBarriers[2] = XfixesImports.XFixesCreatePointerBarrier(
-							_x11Display, Handle, barrierRect.Right, barrierRect.Y, barrierRect.Right, barrierRect.Bottom,
+							_x11Display, Handle, barrierRect.Right, screenRect.Y, barrierRect.Right, screenRect.Bottom,
 							XfixesImports.BarrierDirection.BarrierNegativeX, 0, IntPtr.Zero);
 						// bottom barrier
 						_pointerBarriers[3] = XfixesImports.XFixesCreatePointerBarrier(
-							_x11Display, Handle, barrierRect.X, barrierRect.Bottom, barrierRect.Right, barrierRect.Bottom,
+							_x11Display, Handle, screenRect.X, barrierRect.Bottom, screenRect.Right, barrierRect.Bottom,
 							XfixesImports.BarrierDirection.BarrierNegativeY, 0, IntPtr.Zero);
 					}
 					else