fixed for qt5; removed i3 config requirements

main.cpp

         }
     }
     qDebug() << "Geometry:" << w.geometry();
-    w.show();
+    w.exec();
 
-    return a.exec();
+    return 0;
 }

mainwidget.cpp

 #include "ui_mainwidget.h"
 
 MainWidget::MainWidget(QWidget *parent) :
-    QWidget(parent),
+    QDialog(parent),
     ui(new Ui::MainWidget),
     exitOnLostFocus(false)
 {
     ui->setupUi(this);
+    setWindowFlags( Qt::CustomizeWindowHint );
 }
 
 MainWidget::~MainWidget()

mainwidget.h

 #ifndef MAINWIDGET_H
 #define MAINWIDGET_H
 
-#include <QWidget>
+#include <QDialog>
 #include <QKeyEvent>
 
 namespace Ui {
 class MainWidget;
 }
 
-class MainWidget : public QWidget
+class MainWidget : public QDialog
 {
     Q_OBJECT
 

mainwidget.ui

 <?xml version="1.0" encoding="UTF-8"?>
 <ui version="4.0">
  <class>MainWidget</class>
- <widget class="QWidget" name="MainWidget">
+ <widget class="QDialog" name="MainWidget">
   <property name="geometry">
    <rect>
     <x>0</x>