--- a/gfx/layers/basic/BasicCompositor.cpp
+++ b/gfx/layers/basic/BasicCompositor.cpp
@@ -616,20 +616,16 @@ BasicCompositor::BeginFrame(const nsIntR
   if (!aOpaqueRegion.IsEmpty()) {
     LayoutDeviceIntRegion clearRegion = mInvalidRegion;
     clearRegion.SubOut(LayoutDeviceIntRegion::FromUnknownRegion(aOpaqueRegion));
     clearRect = clearRegion.GetBounds();
   } else {
     clearRect = mInvalidRect;
   }
 
-  // Prevent CreateRenderTargetForWindow from clearing unwanted area.
-  gfxUtils::ClipToRegion(mDrawTarget,
-                         mInvalidRegion.ToUnknownRegion());
-
   // Setup an intermediate render target to buffer all compositing. We will
   // copy this into mDrawTarget (the widget), and/or mTarget in EndFrame()
   RefPtr<CompositingRenderTarget> target =
     CreateRenderTargetForWindow(mInvalidRect,
                                 clearRect,
                                 bufferMode);
   if (!target) {
     if (!mTarget) {
@@ -638,20 +634,18 @@ BasicCompositor::BeginFrame(const nsIntR
     return;
   }
   SetRenderTarget(target);
 
   // We only allocate a surface sized to the invalidated region, so we need to
   // translate future coordinates.
   mRenderTarget->mDrawTarget->SetTransform(Matrix::Translation(-mRenderTarget->GetOrigin()));
 
-  if (mRenderTarget->mDrawTarget != mDrawTarget) {
-    gfxUtils::ClipToRegion(mRenderTarget->mDrawTarget,
-                           mInvalidRegion.ToUnknownRegion());
-  }
+  gfxUtils::ClipToRegion(mRenderTarget->mDrawTarget,
+                         mInvalidRegion.ToUnknownRegion());
 
   if (aRenderBoundsOut) {
     *aRenderBoundsOut = rect;
   }
 
   if (aClipRectIn) {
     mRenderTarget->mDrawTarget->PushClipRect(Rect(*aClipRectIn));
   } else {
@@ -676,20 +670,17 @@ BasicCompositor::EndFrame()
     float b = float(rand()) / RAND_MAX;
     // We're still clipped to mInvalidRegion, so just fill the bounds.
     mRenderTarget->mDrawTarget->FillRect(
       IntRectToRect(mInvalidRegion.GetBounds()).ToUnknownRect(),
       ColorPattern(Color(r, g, b, 0.2f)));
   }
 
   // Pop aInvalidregion
-  mDrawTarget->PopClip();
-  if (mRenderTarget->mDrawTarget != mDrawTarget) {
-    mRenderTarget->mDrawTarget->PopClip();
-  }
+  mRenderTarget->mDrawTarget->PopClip();
 
   if (mTarget || mRenderTarget->mDrawTarget != mDrawTarget) {
     // Note: Most platforms require us to buffer drawing to the widget surface.
     // That's why we don't draw to mDrawTarget directly.
     RefPtr<SourceSurface> source;
     if (mRenderTarget->mDrawTarget != mDrawTarget) {
       source = mWidget->EndBackBufferDrawing();
     } else {