I used one of the examples from ImGui source code (D3d11), I want to remove the ugly default host window that has the title "Dear ImGui DirectX11 Example" (image attached) and only use my own created window (the red one). 
From the code I can see that it is created using this:
// Create application window
//ImGui_ImplWin32_EnableDpiAwareness();
WNDCLASSEXW wc = { sizeof(wc), CS_CLASSDC, WndProc, 0L, 0L, GetModuleHandle(NULL), NULL, NULL, NULL, NULL, L"ImGui Example", NULL };
::RegisterClassExW(&wc);
HWND hwnd = ::CreateWindowW(wc.lpszClassName, L"Dear ImGui DirectX11 Example", WS_OVERLAPPEDWINDOW, 100, 100, 600, 600, NULL, NULL, wc.hInstance, NULL);
