Method NavUpdateWindowing

Source/3rdParty/imgui/imgui.cpp:14544–14738

Windowing management mode Keyboard: Ctrl+Tab (change focus/move/resize), Alt (toggle menu layer) Gamepad: Hold Menu/Square (change focus/move/resize), Tap Menu/Square (toggle menu layer)

// Keyboard: Ctrl+Tab (change focus/move/resize), Alt (toggle menu layer)
// Gamepad:  Hold Menu/Square (change focus/move/resize), Tap Menu/Square (toggle menu layer)
static void ImGui::NavUpdateWindowing()
{
    ImGuiContext& g = *GImGui;
    ImGuiIO& io = g.IO;

    ImGuiWindow* apply_focus_window = NULL;
    bool apply_toggle_layer = false;

    ImGuiWindow* modal_window = GetTopMostPopupModal();
    bool allow_windowing = (modal_window == NULL); // FIXME: This prevent Ctrl+Tab from being usable with windows that are inside the Begin-stack of that modal.
    if (!allow_windowing)
        g.NavWindowingTarget = NULL;

    // Fade out
    if (g.NavWindowingTargetAnim && g.NavWindowingTarget == NULL)
    {
        g.NavWindowingHighlightAlpha = ImMax(g.NavWindowingHighlightAlpha - io.DeltaTime * 10.0f, 0.0f);
        if (g.DimBgRatio <= 0.0f && g.NavWindowingHighlightAlpha <= 0.0f)
            g.NavWindowingTargetAnim = NULL;
    }

    // Start Ctrl+Tab or Square+L/R window selection
    // (g.ConfigNavWindowingKeyNext/g.ConfigNavWindowingKeyPrev defaults are ImGuiMod_Ctrl|ImGuiKey_Tab and ImGuiMod_Ctrl|ImGuiMod_Shift|ImGuiKey_Tab)
    const ImGuiID owner_id = ImHashStr("##NavUpdateWindowing");
    const bool nav_gamepad_active = (io.ConfigFlags & ImGuiConfigFlags_NavEnableGamepad) != 0 && (io.BackendFlags & ImGuiBackendFlags_HasGamepad) != 0;
    const bool nav_keyboard_active = (io.ConfigFlags & ImGuiConfigFlags_NavEnableKeyboard) != 0;
    const bool keyboard_next_window = allow_windowing && g.ConfigNavWindowingKeyNext && Shortcut(g.ConfigNavWindowingKeyNext, ImGuiInputFlags_Repeat | ImGuiInputFlags_RouteAlways, owner_id);
    const bool keyboard_prev_window = allow_windowing && g.ConfigNavWindowingKeyPrev && Shortcut(g.ConfigNavWindowingKeyPrev, ImGuiInputFlags_Repeat | ImGuiInputFlags_RouteAlways, owner_id);
    const bool start_toggling_with_gamepad = nav_gamepad_active && !g.NavWindowingTarget && Shortcut(ImGuiKey_NavGamepadMenu, ImGuiInputFlags_RouteAlways, owner_id);
    const bool start_windowing_with_gamepad = allow_windowing && start_toggling_with_gamepad;
    const bool start_windowing_with_keyboard = allow_windowing && !g.NavWindowingTarget && (keyboard_next_window || keyboard_prev_window); // Note: enabled even without NavEnableKeyboard!
    bool just_started_windowing_from_null_focus = false;
    if (start_toggling_with_gamepad)
    {
        g.NavWindowingToggleLayer = true; // Gamepad starts toggling layer
        g.NavWindowingToggleKey = ImGuiKey_NavGamepadMenu;
        g.NavWindowingInputSource = g.NavInputSource = ImGuiInputSource_Gamepad;
    }
    if (start_windowing_with_gamepad || start_windowing_with_keyboard)
        if (ImGuiWindow* window = (g.NavWindow && IsWindowNavFocusable(g.NavWindow)) ? g.NavWindow : FindWindowNavFocusable(g.WindowsFocusOrder.Size - 1, -INT_MAX, -1))
        {
            if (start_windowing_with_keyboard || g.ConfigNavWindowingWithGamepad)
                g.NavWindowingTarget = g.NavWindowingTargetAnim = window->RootWindow; // Current location
            g.NavWindowingTimer = g.NavWindowingHighlightAlpha = 0.0f;
            g.NavWindowingAccumDeltaPos = g.NavWindowingAccumDeltaSize = ImVec2(0.0f, 0.0f);
            g.NavWindowingInputSource = g.NavInputSource = start_windowing_with_keyboard ? ImGuiInputSource_Keyboard : ImGuiInputSource_Gamepad;
            if (g.NavWindow == NULL)
                just_started_windowing_from_null_focus = true;

            // Manually register ownership of our mods. Using a global route in the Shortcut() calls instead would probably be correct but may have more side-effects.
            if (keyboard_next_window || keyboard_prev_window)
                SetKeyOwnersForKeyChord((g.ConfigNavWindowingKeyNext | g.ConfigNavWindowingKeyPrev) & ImGuiMod_Mask_, owner_id);
        }

    // Gamepad update
    if ((g.NavWindowingTarget || g.NavWindowingToggleLayer) && g.NavWindowingInputSource == ImGuiInputSource_Gamepad)
    {
        if (g.NavWindowingTarget != NULL)