效果预览

实现概要
- 使用Gtk::Paned
- 虽然 Paned 只能装两个子控件, 但是我可以嵌套
paned1 装 box1 和 box2
paned2 装 paned1 和 box3
源代码
#include <gtkmm.h>
class ExampleWindow : public Gtk::Window
{
public:
ExampleWindow()
{
set_title("GTKMM 4 Vertical Multi-Pane Example");
auto box1 = Gtk::make_managed<Gtk::Box>(Gtk::Orientation::VERTICAL,10);
auto box2 = Gtk::make_managed<Gtk::Box>(Gtk::Orientation::VERTICAL,10);
auto box3 = Gtk::make_managed<Gtk::Box>(Gtk::Orientation::VERTICAL,10);
auto pLabel1 = Gtk::make_managed<Gtk::Label>("This is Box 1");
box1->append(*pLabel1);
auto pLabel2 = Gtk::make_managed<Gtk::Label>("This is Box 2")