diff --git a/panels/project.cpp b/panels/project.cpp
index 5b5eb05e0..cb95e69a1 100644
--- a/panels/project.cpp
+++ b/panels/project.cpp
@@ -1246,20 +1246,22 @@ bool Project::load_worker(QFile& f, QXmlStreamReader& stream, int type) {
                                 const TransitionData& td = transition_data.at(i);
                                 Clip* primary = td.otc;
                                 Clip* secondary = td.ctc;
-                                if (primary == NULL) {
-                                    primary = secondary;
-                                    secondary = NULL;
-                                }
-                                const EffectMeta* meta = get_meta_from_name(td.name, (primary->track < 0) ? EFFECT_TYPE_VIDEO : EFFECT_TYPE_AUDIO);
-                                if (meta == NULL) {
-                                    dout << "[WARNING] Failed to link transition with name:" << td.name;
-                                    if (td.otc != NULL) td.otc->opening_transition = -1;
-                                    if (td.ctc != NULL) td.ctc->closing_transition = -1;
-                                } else {
-                                    int transition_index = create_transition(primary, secondary, meta);
-                                    primary->sequence->transitions.at(transition_index)->set_length(td.length);
-                                    if (td.otc != NULL) td.otc->opening_transition = transition_index;
-                                    if (td.ctc != NULL) td.ctc->closing_transition = transition_index;
+                                if (primary != NULL || secondary != NULL) {
+                                    if (primary == NULL) {
+                                        primary = secondary;
+                                        secondary = NULL;
+                                    }
+                                    const EffectMeta* meta = get_meta_from_name(td.name, (primary->track < 0) ? EFFECT_TYPE_VIDEO : EFFECT_TYPE_AUDIO);
+                                    if (meta == NULL) {
+                                        dout << "[WARNING] Failed to link transition with name:" << td.name;
+                                        if (td.otc != NULL) td.otc->opening_transition = -1;
+                                        if (td.ctc != NULL) td.ctc->closing_transition = -1;
+                                    } else {
+                                        int transition_index = create_transition(primary, secondary, meta);
+                                        primary->sequence->transitions.at(transition_index)->set_length(td.length);
+                                        if (td.otc != NULL) td.otc->opening_transition = transition_index;
+                                        if (td.ctc != NULL) td.ctc->closing_transition = transition_index;
+                                    }
                                 }
                             }
 
diff --git a/ui/viewerwidget.cpp b/ui/viewerwidget.cpp
index eb9152270..7329f2e9a 100644
--- a/ui/viewerwidget.cpp
+++ b/ui/viewerwidget.cpp
@@ -24,7 +24,6 @@
 #include <QOpenGLShaderProgram>
 #include <QtMath>
 #include <QOpenGLFramebufferObject>
-#include <QOpenGLFunctions>
 #include <QMouseEvent>
 #include <QMimeData>
 #include <QDrag>
@@ -37,7 +36,7 @@ extern "C" {
 	#include <libavformat/avformat.h>
 }
 
-#define GL_DEFAULT_BLEND glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+#define GL_DEFAULT_BLEND glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_SRC_ALPHA, GL_ONE);
 
 ViewerWidget::ViewerWidget(QWidget *parent) :
 	QOpenGLWidget(parent),
@@ -116,6 +115,8 @@ void ViewerWidget::retry() {
 }
 
 void ViewerWidget::initializeGL() {
+    initializeOpenGLFunctions();
+
     connect(context(), SIGNAL(aboutToBeDestroyed()), this, SLOT(delete_function()), Qt::DirectConnection);
 
 	retry_timer.start();
@@ -347,9 +348,7 @@ void ViewerWidget::process_effect(Clip* c, Effect* e, double timecode, GLTexture
 			if (e->enable_superimpose) {
 				GLuint superimpose_texture = e->process_superimpose(timecode);
                 if (superimpose_texture != 0) {
-                    glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
                     composite_texture = draw_clip(c->fbo[!fbo_switcher], superimpose_texture, false);
-                    GL_DEFAULT_BLEND
                 }
 			}
 		}
@@ -523,6 +522,7 @@ GLuint ViewerWidget::compose_sequence(QVector<Clip*>& nests, bool render_audio)
 
                     fbo_switcher = !fbo_switcher;
 
+                    // set up default coords
                     GLTextureCoords coords;
                     coords.grid_size = 1;
 					coords.vertexTopLeftX = coords.vertexBottomLeftX = -video_width/2;
@@ -534,6 +534,7 @@ GLuint ViewerWidget::compose_sequence(QVector<Clip*>& nests, bool render_audio)
 					coords.textureBottomLeftY = coords.textureBottomRightY = coords.textureTopRightX = coords.textureBottomRightX = 1.0;
                     coords.textureTopLeftQ = coords.textureTopRightQ = coords.textureTopLeftQ = coords.textureBottomLeftQ = 1;
 
+                    // set up autoscale
                     if (c->autoscale && (video_width != s->width && video_height != s->height)) {
                         float width_multiplier = (float) s->width / (float) video_width;
                         float height_multiplier = (float) s->height / (float) video_height;
diff --git a/ui/viewerwidget.h b/ui/viewerwidget.h
index 38837cbaf..a6f9e3632 100644
--- a/ui/viewerwidget.h
+++ b/ui/viewerwidget.h
@@ -8,6 +8,7 @@
 #include <QThread>
 #include <QMutex>
 #include <QWaitCondition>
+#include <QOpenGLFunctions>
 
 class Viewer;
 struct Clip;
@@ -17,7 +18,7 @@ class Effect;
 class EffectGizmo;
 struct GLTextureCoords;
 
-class ViewerWidget : public QOpenGLWidget
+class ViewerWidget : public QOpenGLWidget, QOpenGLFunctions
 {
 	Q_OBJECT
 public: