message: views with custom render target should be blendable
  We made this wrong assumption that views with a custom rendertarget
  are never blended, but it's not true -- e.g. two views can use the
  same rendertarget.
  Fixes
  May impact
diff: @@ -352,9 +352,7 @@ void FRenderer::renderJob(ArenaScope& arena, FView& view) {
  }, viewRenderTarget);
  const bool blendModeTranslucent = view.getBlendMode() == View::BlendMode::TRANSLUCENT;
  - const bool hasCustomRenderTarget = viewRenderTarget != mRenderTarget;
  - // "blending" is meaningless when the view has a custom rendertarget because it's not composited
  - const bool blending = !hasCustomRenderTarget && blendModeTranslucent;
  + const bool blending = blendModeTranslucent;
  // If the swapchain is transparent or if we blend into it, we need to allocate our intermediate
  // buffers with an alpha channel.
  const bool needsAlphaChannel = (mSwapChain ? mSwapChain->isTransparent() : false) || blendModeTranslucent;
  