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Upgraded to Windows 11 24H2 and suddenly your internal overlay is a solid black void? You're not the only one. It looks like the latest Windows build is being picky about how DWM composition and alpha blending are handled for internal DX11 windows, especially when people are reworking their projects for the current environment.
The Problem
When trying to render an internal ImGui overlay (specifically for things like Roblox), the background remains black even though ImGui_ImplWin32_EnableAlphaCompositing is called and the render target is cleared with zero alpha. This usually happens because 24H2 handles window styles and the flip model differently.
Initialization Snippet
Here is the standard setup that seems to be failing on the new build:
Rendering Breakdown
The rendering loop clears the target with { 0.f, 0.f, 0.f, 0.f }, which should result in a fully transparent background, but instead, it creates a black overlay covering the game:
It worked fine on previous builds, so this is definitely a 24H2 specific behavior change regarding how it treats popups and alpha composition.
Anyone else noticed 24H2 nuking legacy DWM composition tricks?
The Problem
When trying to render an internal ImGui overlay (specifically for things like Roblox), the background remains black even though ImGui_ImplWin32_EnableAlphaCompositing is called and the render target is cleared with zero alpha. This usually happens because 24H2 handles window styles and the flip model differently.
Initialization Snippet
Here is the standard setup that seems to be failing on the new build:
Code:
wc = { sizeof(wc), CS_CLASSDC, WndProc, 0L, 0L, GetModuleHandle(nullptr), nullptr, nullptr, nullptr, nullptr, (LPCWSTR)(randomString(20).c_str()), nullptr };
::RegisterClassExW(&wc);
hwnd = ::CreateWindowExW(WS_EX_TOOLWINDOW, wc.lpszClassName, (LPCWSTR)(randomString(20).c_str()), WS_POPUP, 100, 100, 1280, 800, nullptr, nullptr, wc.hInstance, nullptr);
if (!CreateDeviceD3D(hwnd)) return;
::ShowWindow(hwnd, SW_SHOWDEFAULT);
::UpdateWindow(hwnd);
ImGui_ImplWin32_Init(hwnd);
ImGui_ImplWin32_EnableAlphaCompositing(hwnd);
ImGui_ImplDX11_Init(g_pd3dDevice, g_pd3dDeviceContext);Rendering Breakdown
The rendering loop clears the target with { 0.f, 0.f, 0.f, 0.f }, which should result in a fully transparent background, but instead, it creates a black overlay covering the game:
Code:
ImGui::Render();
const float clear_color_with_alpha[4] = { 0.f, 0.f, 0.f, 0.f };
g_pd3dDeviceContext->OMSetRenderTargets(1, &g_mainRenderTargetView, nullptr);
g_pd3dDeviceContext->ClearRenderTargetView(g_mainRenderTargetView, clear_color_with_alpha);
ImGui_ImplDX11_RenderDrawData(ImGui::GetDrawData());
g_pSwapChain->Present(1, 0);- Check if WS_EX_LAYERED is required for your specific window configuration on 24H2.
- Verify that DwmExtendFrameIntoClientArea (which is what the ImGui Win32 helper calls) isn't returning an error code.
- Switching to a flip-model swap chain (DXGI_SWAP_EFFECT_FLIP_DISCARD) with DXGI_ALPHA_MODE_PREMULTIPLIED often resolves transparency issues in modern Windows builds.
- Ensure no other overlays (like Discord or Nvidia) are conflicting with the composition of your window.
It worked fine on previous builds, so this is definitely a 24H2 specific behavior change regarding how it treats popups and alpha composition.
Anyone else noticed 24H2 nuking legacy DWM composition tricks?
