Work around QTBUG-56382 with manual event loop flushing

* See https://bugreports.qt.io/browse/QTBUG-56382 for more details -
  creating DXGI swapchains adds a windows hook, and enough windows hooks
  forces out Qt's internal hook which it relies upon for proper event
  processing.

qrenderdoc/Code/CaptureContext.cpp

@@ -62,6 +62,11 @@ CaptureContext::~CaptureContext()
   delete m_MainWindow;
 }
 
+bool CaptureContext::isRunning()
+{
+  return m_MainWindow && m_MainWindow->isVisible();
+}
+
 void CaptureContext::LoadLogfile(QString logFile, bool temporary)
 {
   LoadLogfile(-1, "", logFile, temporary);

qrenderdoc/Code/CaptureContext.h

@@ -56,6 +56,8 @@ public:
   CaptureContext(QString paramFilename, QString remoteHost, uint32_t remoteIdent, bool temp);
   ~CaptureContext();
 
+  bool isRunning();
+
   //////////////////////////////////////////////////////////////////////////////
   // Control functions
 

qrenderdoc/Code/main.cpp

@@ -95,13 +95,19 @@ int main(int argc, char *argv[])
   argv_mod[argc - 2] = arg;
   argv_mod[argc - 1] = pathChars.data();
 
-  QApplication a(argc, argv_mod);
+  QApplication application(argc, argv_mod);
 
-  CaptureContext ctx(filename, remoteHost, remoteIdent, temp);
+  {
+    CaptureContext ctx(filename, remoteHost, remoteIdent, temp);
 
-  int ret = a.exec();
+    while(ctx.isRunning())
+    {
+      application.processEvents(QEventLoop::WaitForMoreEvents);
+      QCoreApplication::sendPostedEvents();
+    }
+  }
 
   delete[] argv_mod;
 
-  return ret;
+  return 0;
 }