diff --git a/doc/classes/RenderingServer.xml b/doc/classes/RenderingServer.xml
index 5830a8452c..22a9925d4b 100644
--- a/doc/classes/RenderingServer.xml
+++ b/doc/classes/RenderingServer.xml
@@ -3365,7 +3365,8 @@
 			Objects are displayed with only light information.
 		</constant>
 		<constant name="VIEWPORT_DEBUG_DRAW_OVERDRAW" value="3" enum="ViewportDebugDraw">
-			Objects are displayed semi-transparent with additive blending so you can see where they are drawing over top of one another. A higher overdraw means you are wasting performance on drawing pixels that are being hidden behind others.
+			Objects are displayed semi-transparent with additive blending so you can see where they are drawing over top of one another. A higher overdraw (represented by brighter colors) means you are wasting performance on drawing pixels that are being hidden behind others.
+			[b]Note:[/b] When using this debug draw mode, custom shaders will be ignored. This means vertex displacement won't be visible anymore.
 		</constant>
 		<constant name="VIEWPORT_DEBUG_DRAW_WIREFRAME" value="4" enum="ViewportDebugDraw">
 			Debug draw draws objects in wireframe.