diff --git a/Minecraft.Client/glWrapper.cpp b/Minecraft.Client/glWrapper.cpp
index c49620aa..0c5cec6b 100644
--- a/Minecraft.Client/glWrapper.cpp
+++ b/Minecraft.Client/glWrapper.cpp
@@ -123,7 +123,7 @@ void glClearColor(float r, float g, float b, float a)
 
 	RenderManager.SetClearColour(D3DCOLOR_RGBA(ir,ig,ib,ia));
 #else
-	float rgba[4] = {r,g,b,a};
+	float rgba[4] = {r,g,b,1.0f}; // Force alpha=1 to prevent DWM window transparency
 	RenderManager.SetClearColour(rgba);
 #endif
 }