How to correctly handle Window resizing when using ImGui?

Question

I am using ImGui with the aim of creating a Windows Application.

One thing I have noticed and is troubling me a lot is when resizing the Window, it doesn't update the contents (buffers?) correctly, see the attached image:

The black area was captured whilst I was resizing the window to make it larger.

Here is the exact code I am using that produced the image above:

#include "imgui.h"
#include "imgui_impl_glfw.h"
#include "imgui_impl_opengl3.h"
#include <stdio.h>
#define GL_SILENCE_DEPRECATION
#if defined(IMGUI_IMPL_OPENGL_ES2)
#include <GLES2/gl2.h>
#endif
#include <GLFW/glfw3.h>

#if defined(_MSC_VER) && (_MSC_VER >= 1900) && !defined(IMGUI_DISABLE_WIN32_FUNCTIONS)
#pragma comment(lib, "legacy_stdio_definitions")
#endif

GLFWwindow* window = nullptr;

static void glfw_error_callback(int error, const char* description)
{
    fprintf(stderr, "GLFW Error %d: %s\n", error, description);
}

void updateBuffers()
{
    ImGui::Render();
    int display_w, display_h;
    glfwGetFramebufferSize(window, &display_w, &display_h);
    glViewport(0, 0, display_w, display_h);
    glClearColor(0.3f, 0.3f, 0.3f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());

    glfwSwapBuffers(window);
}

void frame_buffer_size_callback(GLFWwindow* window, int width, int height)
{
}

int main(int, char**)
{
    glfwSetErrorCallback(glfw_error_callback);
    if (!glfwInit())
        return 1;

    const char* glsl_version = "#version 130";
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);

    window = glfwCreateWindow(1280, 720, "Dear ImGui GLFW+OpenGL3 example", nullptr, nullptr);
    if (window == nullptr)
        return 1;
    glfwMakeContextCurrent(window);
    glfwSetFramebufferSizeCallback(window, frame_buffer_size_callback);
    glfwSwapInterval(1);

    IMGUI_CHECKVERSION();
    ImGui::CreateContext();
    ImGuiIO& io = ImGui::GetIO(); (void)io;
    io.ConfigFlags |= ImGuiConfigFlags_NavEnableKeyboard;

    ImGui::StyleColorsDark();

    ImGui_ImplGlfw_InitForOpenGL(window, true);
    ImGui_ImplOpenGL3_Init(glsl_version);

    while (!glfwWindowShouldClose(window))
    {
        glfwPollEvents();

        ImGui_ImplOpenGL3_NewFrame();
        ImGui_ImplGlfw_NewFrame();
        ImGui::NewFrame();


        ImGui::Begin("Window");
        ImGui::Text("Hello World!");
        ImGui::End();        

        updateBuffers();
    }

    ImGui_ImplOpenGL3_Shutdown();
    ImGui_ImplGlfw_Shutdown();
    ImGui::DestroyContext();

    glfwDestroyWindow(window);
    glfwTerminate();

    return 0;
}

In the above code I have included the framebuffer_size_callback() in order to capture the window during its resize event, but I am unsure what other changes to make. I have come close where I was able to get the Window to resize more nicely simply by calling my draw logic inside the frame_buffer_size_callback:

void frame_buffer_size_callback(GLFWwindow* window, int width, int height)
{
    updateBuffers();
}

but the ImGui widgets were getting cut off (this occurs when the widget is slightly offscreen and resizing the window bigger):

How can I get the Window to resize nicely keeping the ImGui and OpenGL contents drawn correctly too?