diff --git a/gfx/layers/d3d9/CompositorD3D9.cpp b/gfx/layers/d3d9/CompositorD3D9.cpp
index 8f38678b6546..2a9632c35292 100644
--- a/gfx/layers/d3d9/CompositorD3D9.cpp
+++ b/gfx/layers/d3d9/CompositorD3D9.cpp
@@ -377,7 +377,6 @@ CompositorD3D9::DrawQuad(const gfx::Rect &aRect, const gfx::Rect &aClipRect,
       device()->SetTexture(1, sourceOnWhite->GetD3D9Texture());
       device()->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_ZERO);
       device()->SetRenderState(D3DRS_DESTBLEND, D3DBLEND_INVSRCCOLOR);
-      device()->SetRenderState(D3DRS_SEPARATEALPHABLENDENABLE, TRUE);
       device()->DrawPrimitive(D3DPT_TRIANGLESTRIP, 0, 2);
 
       maskTexture = mDeviceManager->SetShaderMode(DeviceManagerD3D9::COMPONENTLAYERPASS2, maskType);
@@ -388,7 +387,6 @@ CompositorD3D9::DrawQuad(const gfx::Rect &aRect, const gfx::Rect &aClipRect,
       // Restore defaults
       device()->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_ONE);
       device()->SetRenderState(D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA);
-      device()->SetRenderState(D3DRS_SEPARATEALPHABLENDENABLE, FALSE);
       device()->SetTexture(1, NULL);
     }
     return;
@@ -401,14 +399,12 @@ CompositorD3D9::DrawQuad(const gfx::Rect &aRect, const gfx::Rect &aClipRect,
 
   if (!isPremultiplied) {
     device()->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_SRCALPHA);
-    device()->SetRenderState(D3DRS_SEPARATEALPHABLENDENABLE, TRUE);
   }
 
   HRESULT hr = device()->DrawPrimitive(D3DPT_TRIANGLESTRIP, 0, 2);
 
   if (!isPremultiplied) {
     device()->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_ONE);
-    device()->SetRenderState(D3DRS_SEPARATEALPHABLENDENABLE, FALSE);
   }
 }