diff --git a/src/Avalonia.X11/X11Window.cs b/src/Avalonia.X11/X11Window.cs
index 95900f72a04..8e9c92864c7 100644
--- a/src/Avalonia.X11/X11Window.cs
+++ b/src/Avalonia.X11/X11Window.cs
@@ -1103,7 +1103,9 @@ public void Activate()
             else
             {
                 XRaiseWindow(_x11.Display, _handle);
-                XSetInputFocus(_x11.Display, _focusProxy._handle, 0, IntPtr.Zero);
+
+                if (_focusProxy is not null)
+                    XSetInputFocus(_x11.Display, _focusProxy._handle, 0, IntPtr.Zero);
             }
         }