OpenCV / HighGUI draws new windows for each attached object - opencv

Question

I'm working through Learning OpenCV 3 by Kaehler & Bradski.
I've applied all errata fixes to this code per http://www.oreilly.com/catalog/errata.csp?isbn=0636920044765.
Expected behavior: the trackbar should be attached to the namedWindow "Example2-4", then frames from a video file (specified via command-line argument) should be drawn in the same window.
Actual behavior: the trackbar is drawn in one window named "Example2-4", then the frames are drawn in a second window named "Example2-4". Closing either window causes the program to hang. Otherwise the behavior is correct.
Platform: Windows 10, x64, OpenCV 3.3
Edit 1:
I tried adding a string literal to the top of main():
char *window_name = "Window";
and replacing every instance of "Example2-4" with window_name. This didn't change the behavior.
Edit 2:
This code is the first time I've tried to add an interactive widget, but adding images and video frames to windows in previous examples also generated two windows with the same name. I suspect I'm up against a configuration issue, but I still have no idea how to solve it.
Edit 3: I've added code for the simplest program that will demonstrate the problem behavior, and changed the title of this post to characterize it better.
Code:
/* Windows precompiled headers */
//#include "stdafx.h"
/* C++ */
#include <iostream>
#include <fstream>
/* OpenCv */
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
using namespace std;
int g_slider_position = 0;
int g_run = 1, g_dontset = 0; // start out in single step mode
cv::VideoCapture g_cap;
void onTrackBarSlide(int pos, void *);
int main(int argc, char **argv)
{
cv::namedWindow("Example2-4", CV_WINDOW_AUTOSIZE);
g_cap.open(string(argv[1]));
int frames = (int)g_cap.get(CV_CAP_PROP_FRAME_COUNT);
int tmpw = (int)g_cap.get(CV_CAP_PROP_FRAME_WIDTH);
int tmph = (int)g_cap.get(CV_CAP_PROP_FRAME_HEIGHT);
cout << "Video has " << frames << " frames of dimensions ("
<< tmpw << ", " << tmph << ")." << endl;
cv::createTrackbar("Position", "Example2-4", &g_slider_position, frames,
onTrackBarSlide);
cv::Mat frame;
for (;;) {
if (g_run != 0) {
g_cap >> frame;
if (frame.empty())
break;
int current_pos = (int)g_cap.get(CV_CAP_PROP_POS_FRAMES);
g_dontset = 1;
cv::setTrackbarPos("Position", "Example2-4", current_pos);
cv::imshow("Example2-4", frame);
g_run -= 1;
}
char c = (char)cv::waitKey(10);
if (c == 's') { // single step
g_run = 1;
cout << "Single step, run = " << g_run << endl;
}
if (c == 'r') { // run mode
g_run = -1;
cout << "Run mode, run = " << g_run << endl;
}
if (c == 27)
break;
}
return 0;
}
void onTrackBarSlide(int pos, void *) {
g_cap.set(CV_CAP_PROP_POS_FRAMES, pos);
if (!g_dontset)
g_run = 1;
g_dontset = 0;
}
Simplest code which results in problem behavior. Gets an image via command line argument:
#include <opencv2\opencv.hpp>
int main(int argc, char **argv)
{
char *window_name = "Window";
cv::Mat img = cv::imread(argv[1], -1);
if (img.empty())
return -1;
cv::namedWindow(window_name, CV_WINDOW_AUTOSIZE);
cv::imshow(window_name, img);
cv::waitKey(0);
cv::destroyWindow(window_name);
return 0;
}