Method PushColumnsBackground

core/src/imgui/imgui_tables.cpp:3749–3760

Get into the columns background draw command (which is generally the same draw command as before we called BeginColumns)

// Get into the columns background draw command (which is generally the same draw command as before we called BeginColumns)
void ImGui::PushColumnsBackground()
{
    ImGuiWindow* window = GetCurrentWindowRead();
    ImGuiOldColumns* columns = window->DC.CurrentColumns;
    if (columns->Count == 1)
        return;

    // Optimization: avoid SetCurrentChannel() + PushClipRect()
    columns->HostBackupClipRect = window->ClipRect;
    SetWindowClipRectBeforeSetChannel(window, columns->HostInitialClipRect);
    columns->Splitter.SetCurrentChannel(window->DrawList, 0);
}

void ImGui::PopColumnsBackground()
{