Method DockNodeUpdateTabBar

extern/imgui/imgui.cpp:16075–16342

Submit the tab bar corresponding to a dock node and various housekeeping details.

// Submit the tab bar corresponding to a dock node and various housekeeping details.
static void ImGui::DockNodeUpdateTabBar(ImGuiDockNode* node, ImGuiWindow* host_window)
{
    ImGuiContext& g = *GImGui;
    ImGuiStyle& style = g.Style;

    const bool node_was_active = (node->LastFrameActive + 1 == g.FrameCount);
    const bool closed_all = node->WantCloseAll && node_was_active;
    const ImGuiID closed_one = node->WantCloseTabId && node_was_active;
    node->WantCloseAll = false;
    node->WantCloseTabId = 0;

    // Decide if we should use a focused title bar color
    bool is_focused = false;
    ImGuiDockNode* root_node = DockNodeGetRootNode(node);
    if (IsDockNodeTitleBarHighlighted(node, root_node))
        is_focused = true;

    // Hidden tab bar will show a triangle on the upper-left (in Begin)
    if (node->IsHiddenTabBar() || node->IsNoTabBar())
    {
        node->VisibleWindow = (node->Windows.Size > 0) ? node->Windows[0] : NULL;
        node->IsFocused = is_focused;
        if (is_focused)
            node->LastFrameFocused = g.FrameCount;
        if (node->VisibleWindow)
        {
            // Notify root of visible window (used to display title in OS task bar)
            if (is_focused || root_node->VisibleWindow == NULL)
                root_node->VisibleWindow = node->VisibleWindow;
            if (node->TabBar)
                node->TabBar->VisibleTabId = node->VisibleWindow->TabId;
        }
        return;
    }

    // Move ourselves to the Menu layer (so we can be accessed by tapping Alt) + undo SkipItems flag in order to draw over the title bar even if the window is collapsed
    bool backup_skip_item = host_window->SkipItems;
    if (!node->IsDockSpace())
    {
        host_window->SkipItems = false;
        host_window->DC.NavLayerCurrent = ImGuiNavLayer_Menu;
    }

    // Use PushOverrideID() instead of PushID() to use the node id _without_ the host window ID.
    // This is to facilitate computing those ID from the outside, and will affect more or less only the ID of the collapse button, popup and tabs,
    // as docked windows themselves will override the stack with their own root ID.
    PushOverrideID(node->ID);
    ImGuiTabBar* tab_bar = node->TabBar;
    bool tab_bar_is_recreated = (tab_bar == NULL); // Tab bar are automatically destroyed when a node gets hidden
    if (tab_bar == NULL)
    {
        DockNodeAddTabBar(node);
        tab_bar = node->TabBar;
    }

    ImGuiID focus_tab_id = 0;
    node->IsFocused = is_focused;