I have 2 boxes and actionbars. when I add box2 as a child to the window. When I remove the code that adds the box2 to the window, these errors appear when I try to run the compiled app. No errors at compilation but there are errors when I try to run the app.

These are the errors:

(BIDE:12460): GLib-GObject-CRITICAL **: 22:50:34.898: invalid uninstantiatable type '(null)' in cast to 'GtkWidget'

(BIDE:12460): Gtk-CRITICAL **: 22:50:34.898: gtk_widget_get_parent: assertion 'GTK_IS_WIDGET (widget)' failed

(BIDE:12460): Gtk-CRITICAL **: 22:50:34.898: gtk_widget_insert_before: assertion 'GTK_IS_WIDGET (widget)' failed

(BIDE:12460): Gtk-CRITICAL **: 22:50:34.940: gtk_widget_get_visible: assertion 'GTK_IS_WIDGET (widget)' failed

(BIDE:12460): Gtk-CRITICAL **: 22:50:34.940: gtk_widget_child_focus: assertion 'GTK_IS_WIDGET (widget)' failed
Segmentation fault (core dumped)

This is my current code:

#include <gtk/gtk.h>
#include <pango/pango.h>
#include <stdio.h>

//char verString[5] = "0.0.1";
char buffer[100];
//READERS! This code is meant to be easily read for people who want to learn!
GtkWidget *helpWindow;
static void showWindow() {
    gtk_window_present(GTK_WINDOW(helpWindow));
//  gtk_widget_set_visible(GTK_WIDGET(windowToOpen), true); 

}

//Handles initializing the window
static void activateWindow(GtkApplication *app) {
    GtkWidget *window = gtk_application_window_new(app);
    helpWindow = gtk_application_window_new(app);
    GtkWidget *sw = gtk_scrolled_window_new();
    gtk_widget_set_vexpand(sw, TRUE);

    //Info Bar | Bottom
    GtkWidget *infoBar = gtk_action_bar_new();
    GtkWidget *box2 = gtk_box_new(GTK_ORIENTATION_VERTICAL, 0);
    gtk_window_set_child(GTK_WINDOW(window), box2);
    GtkWidget *sw2 = gtk_scrolled_window_new();
    gtk_widget_set_vexpand(sw2, TRUE);
    gtk_box_append(GTK_BOX(box2), infoBar);
    gtk_box_append(GTK_BOX(box2), sw2);



    GtkWidget *verInfo = gtk_label_new("Testing");
    gtk_action_bar_pack_start(GTK_ACTION_BAR(infoBar), GTK_WIDGET(verInfo));
    gtk_widget_set_size_request(GTK_WIDGET(verInfo),-1, 200);
    
    

    //Stuff for help window
    GtkWidget *ytURI = gtk_link_button_new_with_label("https://www.youtube.com/channel/UCvECibTCuY1Txj_DtZTddKQ", "My YouTube");
    GtkWidget *gitURI = gtk_link_button_new_with_label("https://github.com/thatitalianguy08", "My Github");
    gtk_window_set_child(GTK_WINDOW(helpWindow), GTK_WIDGET(ytURI));
    gtk_window_set_child(GTK_WINDOW(helpWindow), GTK_WIDGET(gitURI));
    
    //TopActionBar | Creation
    GtkWidget *topActionBar = gtk_action_bar_new();
    GtkWidget *box = gtk_box_new(GTK_ORIENTATION_VERTICAL, 5);
    gtk_window_set_child(GTK_WINDOW(window), GTK_WIDGET(box));
    gtk_box_append(GTK_BOX(box), topActionBar);
    gtk_box_append(GTK_BOX(box), sw);

    

        //TopActionBar | TITLE
        GtkWidget *bideLabel = gtk_label_new(NULL);
        gchar *bideLabelText = g_markup_printf_escaped("<b>BIDE</b>");
        gtk_label_set_markup(GTK_LABEL(bideLabel), bideLabelText);
        gtk_action_bar_pack_start(GTK_ACTION_BAR(topActionBar), GTK_WIDGET(bideLabel));
        gtk_widget_set_size_request(GTK_WIDGET(bideLabel), -1, 50);
        //TopActionBar | Open Folder Button
        GtkWidget *openFolder = gtk_button_new();
        gtk_button_set_label(GTK_BUTTON(openFolder), "Open Folder");
        gtk_action_bar_pack_start(GTK_ACTION_BAR(topActionBar), GTK_WIDGET(openFolder));
        gtk_widget_set_size_request(GTK_WIDGET(openFolder), -1, 50);

        //TopActionBar | Help Menu Button
        gchar *helpButtonText = g_markup_printf_escaped("<u>HELP</u>");
        GtkWidget *helpButton = gtk_button_new();
        GtkWidget *helpLabel = gtk_label_new("Help");
        gtk_label_set_markup(GTK_LABEL(helpLabel), helpButtonText);
        g_signal_connect_swapped(helpButton, "clicked", G_CALLBACK(showWindow), NULL);  
        gtk_widget_set_size_request(GTK_WIDGET(helpButton), -1, 50);
        gtk_button_set_child(GTK_BUTTON(helpButton), GTK_WIDGET(helpLabel));

        //TopActionBar | Save Button
        GtkWidget *saveButton = gtk_button_new_with_label("Save File");
        gtk_widget_set_size_request(GTK_WIDGET(saveButton), -1, 50);
        gtk_action_bar_pack_start(GTK_ACTION_BAR(topActionBar), GTK_WIDGET(saveButton));
        
    
                
        gtk_action_bar_pack_start(GTK_ACTION_BAR(topActionBar), GTK_WIDGET(helpButton));
    gtk_window_set_hide_on_close(GTK_WINDOW(helpWindow), true);
    gtk_window_set_child(GTK_WINDOW(window), GTK_WIDGET(box));
    gtk_window_set_child(GTK_WINDOW(window), GTK_WIDGET(box2));
    gtk_window_present(GTK_WINDOW(window));
    

}

//Main stuff
int main(int argc, char *argv[]){
    GtkApplication *app = gtk_application_new("me.lufthor.bide", G_APPLICATION_DEFAULT_FLAGS);
    g_signal_connect(app, "activate", G_CALLBACK(activateWindow), NULL);
    return g_application_run(G_APPLICATION(app), argc, argv);

}

I’ve tried re writing the code for the box2/infoBar.