viewer: fix mouse and compositing issues from using windows

app/panel/audiomonitor/audiomonitor.cpp

@@ -20,18 +20,35 @@
 
 #include "audiomonitor.h"
 
+#include "panel/panelmanager.h"
+
 namespace olive {
 
+#define super PanelWidget
+
 AudioMonitorPanel::AudioMonitorPanel(QWidget *parent) :
-  PanelWidget(QStringLiteral("AudioMonitor"), parent)
+  super(QStringLiteral("AudioMonitor"), parent)
 {
   audio_monitor_ = new AudioMonitor();
 
+  audio_monitor_->installEventFilter(this);
+
   setWidget(QWidget::createWindowContainer(audio_monitor_));
 
   Retranslate();
 }
 
+bool AudioMonitorPanel::eventFilter(QObject *o, QEvent *e)
+{
+  if (o == audio_monitor_ && e->type() == QEvent::FocusIn) {
+    // HACK: QWindow focus isn't accounted for in QApplication::focusChanged, so we handle it
+    //       manually here.
+    PanelManager::instance()->FocusChanged(nullptr, this);
+  }
+
+  return super::eventFilter(o, e);
+}
+
 void AudioMonitorPanel::Retranslate()
 {
   SetTitle(tr("Audio Monitor"));

app/panel/audiomonitor/audiomonitor.h

@@ -45,6 +45,8 @@ public:
     audio_monitor_->SetParams(params);
   }
 
+  virtual bool eventFilter(QObject *o, QEvent *e) override;
+
 private:
   virtual void Retranslate() override;