diff --git a/plugins/GSdx/GSTextureFX9.cpp b/plugins/GSdx/GSTextureFX9.cpp
index 4e75e3f058..d80446830c 100644
--- a/plugins/GSdx/GSTextureFX9.cpp
+++ b/plugins/GSdx/GSTextureFX9.cpp
@@ -310,6 +310,7 @@ void GSDevice9::SetupOM(OMDepthStencilSelector dssel, OMBlendSelector bsel, uint
 			}
 		}
 
+		// this is not a typo; dx9 uses BGRA rather than the gs native RGBA, unlike dx10
 		if(bsel.wr) bs->RenderTargetWriteMask |= D3DCOLORWRITEENABLE_BLUE;
 		if(bsel.wg) bs->RenderTargetWriteMask |= D3DCOLORWRITEENABLE_GREEN;
 		if(bsel.wb) bs->RenderTargetWriteMask |= D3DCOLORWRITEENABLE_RED;