Windows: After showing QZ window (1s delay) try to check as default and show dialogs as child of QZ window.

- Closes #1632

src/lib/app/mainapplication.cpp

@@ -681,8 +681,9 @@ void MainApplication::postLaunch()
     connect(this, SIGNAL(messageReceived(QString)), this, SLOT(messageReceived(QString)));
     connect(this, SIGNAL(aboutToQuit()), this, SLOT(saveSettings()));
 
-    checkDefaultWebBrowser();
     QtWin::createJumpList();
+
+    QTimer::singleShot(1000, this, SLOT(checkDefaultWebBrowser()));
 }
 
 void MainApplication::saveSession()

src/lib/app/mainapplication.h

@@ -128,6 +128,7 @@ private slots:
     void messageReceived(const QString &message);
     void windowDestroyed(QObject* window);
     void onFocusChanged();
+    void checkDefaultWebBrowser();
 
     void downloadRequested(QWebEngineDownloadItem *download);
 
@@ -143,7 +144,6 @@ private:
 
     void translateApp();
     void backupSavedSessions();
-    void checkDefaultWebBrowser();
 
     void setUserStyleSheet(const QString &filePath);
 

src/lib/other/registerqappassociation.cpp

@@ -18,6 +18,8 @@
 * ============================================================ */
 
 #include "registerqappassociation.h"
+#include "mainapplication.h"
+#include "browserwindow.h"
 
 #include "ShlObj.h"
 #include <QMessageBox>
@@ -105,7 +107,7 @@ bool RegisterQAppAssociation::registerAppCapabilities()
         capabilitiesKey = regLocalMachine.value("Software/RegisteredApplications/" + _appRegisteredName).toString();
 
         if (capabilitiesKey.isEmpty()) {
-            QMessageBox::warning(0, tr("Warning!"),
+            QMessageBox::warning(mApp->getWindow(), tr("Warning!"),
                                  tr("There are some problems. Please, reinstall QupZilla.\n"
                                     "Maybe relaunch with administrator right do a magic for you! ;)"));
             return false;