diff --git a/panels/panels.cpp b/panels/panels.cpp
index dbb22481a..3c4a2d057 100644
--- a/panels/panels.cpp
+++ b/panels/panels.cpp
@@ -113,6 +113,10 @@ void free_panels() {
 }
 
 void scroll_to_frame_internal(QScrollBar* bar, long frame, double zoom, int area_width) {
+  if (bar->value() == bar->minimum() || bar->value() == bar->maximum()) {
+    return;
+  }
+
   int screen_point = getScreenPointFromFrame(zoom, frame) - bar->value();
   int min_x = area_width*0.1;
   int max_x = area_width-min_x;
diff --git a/rendering/audio.cpp b/rendering/audio.cpp
index b27e73a98..183479683 100644
--- a/rendering/audio.cpp
+++ b/rendering/audio.cpp
@@ -419,5 +419,14 @@ QObject* GetAudioWakeObject()
 
 void SetAudioWakeObject(QObject *o)
 {
+  audio_wake_mutex.lock();
   audio_wake_object = o;
+  audio_wake_mutex.unlock();
+}
+
+void WakeAudioWakeObject() {
+  QObject* audio_wake_object = GetAudioWakeObject();
+  if (audio_wake_object != nullptr) {
+    QMetaObject::invokeMethod(audio_wake_object, "play_wake", Qt::QueuedConnection);
+  }
 }
diff --git a/rendering/audio.h b/rendering/audio.h
index 42af7975d..4721766cf 100644
--- a/rendering/audio.h
+++ b/rendering/audio.h
@@ -67,6 +67,7 @@ void clear_audio_ibuffer();
 
 QObject *GetAudioWakeObject();
 void SetAudioWakeObject(QObject* o);
+void WakeAudioWakeObject();
 
 int current_audio_freq();
 
diff --git a/rendering/cacher.cpp b/rendering/cacher.cpp
index 1b793c186..a4df18c65 100644
--- a/rendering/cacher.cpp
+++ b/rendering/cacher.cpp
@@ -461,10 +461,7 @@ void Cacher::CacheAudioWorker() {
   }
 
   // If there's a QObject waiting for audio to be rendered, wake it now
-  QObject* audio_wake_object = GetAudioWakeObject();
-  if (audio_wake_object != nullptr) {
-    QMetaObject::invokeMethod(audio_wake_object, "play_wake", Qt::QueuedConnection);
-  }
+  WakeAudioWakeObject();
 }
 
 bool Cacher::IsReversed()
diff --git a/rendering/renderfunctions.cpp b/rendering/renderfunctions.cpp
index 889474e79..c4c45fcd2 100644
--- a/rendering/renderfunctions.cpp
+++ b/rendering/renderfunctions.cpp
@@ -630,8 +630,8 @@ GLuint olive::rendering::compose_sequence(ComposeSequenceParams &params) {
     }
   }
 
-  if (audio_track_count == 0 && params.viewer != nullptr) {
-    params.viewer->play_wake();
+  if (audio_track_count == 0) {
+    WakeAudioWakeObject();
   }
 
   if (params.video) {
diff --git a/ui/timelineheader.cpp b/ui/timelineheader.cpp
index 96c07b66c..f39065b4f 100644
--- a/ui/timelineheader.cpp
+++ b/ui/timelineheader.cpp
@@ -67,9 +67,9 @@ TimelineHeader::TimelineHeader(QWidget *parent) :
   in_visible(0),
   fm(font()),
   dragging_markers(false),
-  scroll(0)
+  scroll(0),
+  height_actual(fm.height())
 {
-  height_actual = fm.height();
   setCursor(Qt::ArrowCursor);
   setMouseTracking(true);
   setFocusPolicy(Qt::ClickFocus);