Can you support ImGuiConfigFlags_ViewportsEnable from the ImGui docking branch?

[RAVER0306]

io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;  // Enable Keyboard Controls
io.ConfigFlags |= ImGuiConfigFlags_NavEnableGamepad;   // Enable Gamepad Controls
io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;      // Enable Docking
io.ConfigFlags |= ImGuiConfigFlags_ViewportsEnable;    // Enable Multi-Viewport
io.ConfigViewportsNoAutoMerge = true;



if (io.ConfigFlags & ImGuiConfigFlags_ViewportsEnable)
{
    ImGui::UpdatePlatformWindows();
    ImGui::RenderPlatformWindowsDefault();
}