diff --git a/src/main.cpp b/src/main.cpp
index 0239555..46532b8 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1,192 +1,189 @@
 /*
  *  This file is part of KDiff3.
  *
  * SPDX-FileCopyrightText: 2002-2011 Joachim Eibl, joachim.eibl at gmx.de
  * SPDX-FileCopyrightText: 2018-2020 Michael Reeves reeves.87@gmail.com
  * SPDX-License-Identifier: GPL-2.0-or-later
 */
 #include "kdiff3_shell.h"
 #include "version.h"
 
 #include "Logging.h"
 
 #include <stdio.h>// for fileno, stderr
 #include <stdlib.h>// for exit
 
 #ifndef Q_OS_WIN
 #include <unistd.h>
 #endif
 
 #include <KAboutData>
 #include <KCrash/KCrash>
 #include <KLocalizedString>
 #include <KMessageBox>
 
 #include <QApplication>
 #include <QCommandLineOption>
 #include <QCommandLineParser>
 #include <QFile>
 #include <QPointer>
 #include <QStringList>
 #include <QStandardPaths>
 #include <QTextStream>
 
 void initialiseCmdLineArgs(QCommandLineParser* cmdLineParser)
 {
     QString configFileName = QStandardPaths::locate(QStandardPaths::GenericConfigLocation, "kdiff3rc");
     QFile configFile(configFileName);
     QString ignorableOptionsLine = "-u;-query;-html;-abort";
     if(configFile.open(QIODevice::ReadOnly))
     {
         QTextStream ts(&configFile);
         while(!ts.atEnd())
         {
             QString line = ts.readLine();
             if(line.startsWith(QLatin1String("IgnorableCmdLineOptions=")))
             {
                 int pos = line.indexOf('=');
                 if(pos >= 0)
                 {
                     ignorableOptionsLine = line.mid(pos + 1);
                 }
                 break;
             }
         }
     }
     //support our own old preferences this is obsolete
     QStringList sl = ignorableOptionsLine.split(',');
 
     if(!sl.isEmpty())
     {
         const QStringList ignorableOptions = sl.front().split(';');
         for(QString ignorableOption : ignorableOptions)
         {
             ignorableOption.remove('-');
             if(!ignorableOption.isEmpty())
             {
                 if(ignorableOption.length() == 1) {
                     cmdLineParser->addOption(QCommandLineOption({ignorableOption, QLatin1String("ignore")}, i18n("Ignored. (User defined.)")));
                 }
                 else
                 {
                     cmdLineParser->addOption(QCommandLineOption(ignorableOption, i18n("Ignored. (User defined.)")));
                 }
             }
         }
     }
 }
 
 int main(int argc, char* argv[])
 {
     constexpr QLatin1String appName("kdiff3", sizeof("kdiff3") - 1);
 
     QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
     QApplication app(argc, argv); // KAboutData and QCommandLineParser depend on this being setup.
     KLocalizedString::setApplicationDomain(appName.data());
 
     KCrash::initialize();
 
     const QString i18nName = i18n("KDiff3");
     QString appVersion(KDIFF3_VERSION_STRING);
 
     if(sizeof(void*) == 8)
         appVersion += i18n(" (64 bit)");
     else if(sizeof(void*) == 4)
         appVersion += i18n(" (32 bit)");
     const QString description = i18n("Tool for Comparison and Merge of Files and Folders");
     const QString copyright = i18n("(c) 2002-2014 Joachim Eibl, (c) 2017 Michael Reeves KF5/Qt5 port");
     const QString homePage = QStringLiteral("https://kde.org/applications/development/kdiff3");
 
     KAboutData aboutData(appName, i18nName,
                          appVersion, description, KAboutLicense::GPL_V2, copyright, QString(),
                          homePage);
 
     KAboutData::setApplicationData(aboutData);
 
     QCommandLineParser* cmdLineParser = KDiff3Shell::getParser();
     cmdLineParser->setApplicationDescription(aboutData.shortDescription());
 
     aboutData.setupCommandLine(cmdLineParser);
 
     initialiseCmdLineArgs(cmdLineParser);
     // ignorable command options
     cmdLineParser->addOption(QCommandLineOption({QLatin1String("m"), QLatin1String("merge")}, i18n("Merge the input.")));
     cmdLineParser->addOption(QCommandLineOption({QLatin1String("b"), QLatin1String("base")}, i18n("Explicit base file. For compatibility with certain tools."), QLatin1String("file")));
     cmdLineParser->addOption(QCommandLineOption({QLatin1String("o"), QLatin1String("output")}, i18n("Output file. Implies -m. E.g.: -o newfile.txt"), QLatin1String("file")));
     cmdLineParser->addOption(QCommandLineOption(QLatin1String("out"), i18n("Output file, again. (For compatibility with certain tools.)"), QLatin1String("file")));
 #ifdef ENABLE_AUTO
     cmdLineParser->addOption(QCommandLineOption(QLatin1String("auto"), i18n("No GUI if all conflicts are auto-solvable. (Needs -o file)")));
     cmdLineParser->addOption(QCommandLineOption(QLatin1String("noauto"), i18n("Ignore --auto and always show GUI.")));
 #else
     cmdLineParser->addOption(QCommandLineOption(QLatin1String("noauto"), i18n("Ignored.")));
     cmdLineParser->addOption(QCommandLineOption(QLatin1String("auto"), i18n("Ignored.")));
 #endif
     cmdLineParser->addOption(QCommandLineOption(QLatin1String("qall"), i18n("Do not solve conflicts automatically.")));
     cmdLineParser->addOption(QCommandLineOption(QLatin1String("L1"), i18n("Visible name replacement for input file 1 (base)."), QLatin1String("alias1")));
     cmdLineParser->addOption(QCommandLineOption(QLatin1String("L2"), i18n("Visible name replacement for input file 2."), QLatin1String("alias2")));
     cmdLineParser->addOption(QCommandLineOption(QLatin1String("L3"), i18n("Visible name replacement for input file 3."), QLatin1String("alias3")));
     cmdLineParser->addOption(QCommandLineOption({QLatin1String("L"), QLatin1String("fname")}, i18n("Alternative visible name replacement. Supply this once for every input."), QLatin1String("alias")));
     cmdLineParser->addOption(QCommandLineOption(QLatin1String("cs"), i18n("Override a config setting. Use once for every setting. E.g.: --cs \"AutoAdvance=1\""), QLatin1String("string")));
     cmdLineParser->addOption(QCommandLineOption(QLatin1String("confighelp"), i18n("Show list of config settings and current values.")));
     cmdLineParser->addOption(QCommandLineOption(QLatin1String("config"), i18n("Use a different config file."), QLatin1String("file")));
 
     // other command options
     cmdLineParser->addPositionalArgument(QLatin1String("[File1]"), i18n("file1 to open (base, if not specified via --base)"));
     cmdLineParser->addPositionalArgument(QLatin1String("[File2]"), i18n("file2 to open"));
     cmdLineParser->addPositionalArgument(QLatin1String("[File3]"), i18n("file3 to open"));
 
     bool isAtty = true;
 
 #ifndef Q_OS_WIN
     isAtty = isatty(fileno(stderr)) == 1;//will be true for redirected output as well
 #endif
     /*
         QCommandLineParser::process does what is expected on windows or when running from a commandline.
         However, it only accounts for a lack of terminal output on windows.
     */
     if(isAtty)
     {
         cmdLineParser->process(QCoreApplication::arguments());
     }
     else
     {
         /*
             There is no terminal connected so don't just exit mysteriously on error.
         */
         if(!cmdLineParser->parse(QCoreApplication::arguments()))
         {
             QString errorMessage = cmdLineParser->errorText();
 
             KMessageBox::error(nullptr, "<html><head/><body><h2>" + errorMessage + "</h2><pre>" + i18n("See kdiff3 --help for supported options.") + "</pre></body></html>", aboutData.displayName());
             exit(1);
         }
 
         if(cmdLineParser->isSet(QStringLiteral("version"))) {
             KMessageBox::information(nullptr,
                                     aboutData.displayName() + ' ' + aboutData.version(), aboutData.displayName());
             exit(0);
         }
         if(cmdLineParser->isSet(QStringLiteral("help"))) {
             KMessageBox::information(nullptr, "<html><head/><body><pre>" + cmdLineParser->helpText() + "</pre></body></html>", aboutData.displayName());
 
             exit(0);
         }
     }
 
     aboutData.processCommandLine(cmdLineParser);
 
     /*
       Do not attempt to call show here that will be done later.
       This variable exists solely to insure the KDiff3Shell is deleted on exit.
     */
     QPointer<KDiff3Shell> p(new KDiff3Shell());
     Q_UNUSED(p);
 
-    //p->setWindowState( p->windowState() | Qt::WindowActive ); // Patch for ubuntu: window not active on startup
-    //app.installEventFilter( new CFilter );
     int retVal = QApplication::exec();
-    /*  if (QApplication::clipboard()->text().size() == 0)
-     QApplication::clipboard()->clear(); // Patch for Ubuntu: Fix issue with Qt clipboard*/
+    p.clear();
     return retVal;
 }