diff --git a/Configuring-touch-screens-as-subscreen.md b/Configuring-touch-screens-as-subscreen.md
index 6722ebf..a3890dc 100644
--- a/Configuring-touch-screens-as-subscreen.md
+++ b/Configuring-touch-screens-as-subscreen.md
@@ -49,6 +49,9 @@ It's helpful to understand that Windows doesn't know if your second display has
 
 ## Step by step instructions
 
+> [!CAUTION]
+> This assumes that you are running in full screen. Windowed mode is considered a hack, and will not work perfectly well with touch monitors.
+
 1. Connect your touch screen (usually, HDMI for display, USB for touch input, and power)
 1. Make sure it can display things, and touching on the screen results in input. Confirm by dragging around on the Windows desktop. You probably see the selection lasso on the touch screen, right underneath your fingers.
 1. In Windows display settings, ensure that your main monitor is set to primary - **not** the touch screen.