diff --git a/src/infoitem.cpp b/src/infoitem.cpp
index 99982696..00dd1148 100644
--- a/src/infoitem.cpp
+++ b/src/infoitem.cpp
@@ -3,7 +3,6 @@
 #include "config.h"
 #include "infoitem.h"
 
-
 #define PADDING     10
 
 InfoItem::InfoItem(QGraphicsItem *parent) : QGraphicsItem(parent)
@@ -11,24 +10,21 @@ InfoItem::InfoItem(QGraphicsItem *parent) : QGraphicsItem(parent)
 
 }
 
-QRectF InfoItem::boundingRect() const
+void InfoItem::updateBoundingRect()
 {
 	QFont font;
 	font.setPixelSize(FONT_SIZE);
 	font.setFamily(FONT_FAMILY);
 	QFontMetrics fm(font);
 	QList<KV>::const_iterator i;
-	int width = 0;
-
-	if (_list.isEmpty())
-		return QRectF();
+	qreal width = 0;
 
 	for (i = _list.constBegin(); i != _list.constEnd(); i++) {
 		width += fm.width(i->key + ": ");
 		width += fm.width(i->value) + ((i == _list.end() - 1) ? 0 : PADDING);
 	}
 
-	return QRectF(0, 0, width, fm.height());
+	_boundingRect = QRectF(0, 0, width, _list.isEmpty() ? 0 : fm.height());
 }
 
 void InfoItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
@@ -74,5 +70,13 @@ void InfoItem::insert(const QString &key, const QString &value)
 	else
 		_list[i] = kv;
 
+	updateBoundingRect();
+	prepareGeometryChange();
+}
+
+void InfoItem::clear()
+{
+	_list.clear();
+	updateBoundingRect();
 	prepareGeometryChange();
 }
diff --git a/src/infoitem.h b/src/infoitem.h
index fda481aa..74fa6fcc 100644
--- a/src/infoitem.h
+++ b/src/infoitem.h
@@ -9,14 +9,16 @@ class InfoItem : public QGraphicsItem
 public:
 	InfoItem(QGraphicsItem *parent = 0);
 
-	QRectF boundingRect() const;
+	QRectF boundingRect() const {return _boundingRect;}
 	void paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
 	  QWidget *widget);
 
 	void insert(const QString &key, const QString &value);
-	void clear() {_list.clear();}
+	void clear();
 
 private:
+	void updateBoundingRect();
+
 	class KV {
 	public:
 		QString key;
@@ -29,6 +31,7 @@ private:
 	};
 
 	QList<KV> _list;
+	QRectF _boundingRect;
 };
 
 #endif // INFOITEM_H
diff --git a/src/scaleitem.cpp b/src/scaleitem.cpp
index 714f8cae..122e2a37 100644
--- a/src/scaleitem.cpp
+++ b/src/scaleitem.cpp
@@ -17,11 +17,9 @@ ScaleItem::ScaleItem(QGraphicsItem *parent) : QGraphicsItem(parent)
 	_units = Metric;
 	_zoom = ZOOM_MIN;
 	_lat = 0;
-
-	computeScale();
 }
 
-QRectF ScaleItem::boundingRect() const
+void ScaleItem::updateBoundingRect()
 {
 	QFont font;
 	font.setPixelSize(FONT_SIZE);
@@ -33,7 +31,7 @@ QRectF ScaleItem::boundingRect() const
 	es = fm.tightBoundingRect(QString::number(_length * SEGMENTS));
 	us = fm.tightBoundingRect(units());
 
-	return QRectF(-ss.width()/2, 0,
+	_boundingRect = QRectF(-ss.width()/2, 0,
 	  _width * SEGMENTS + ss.width()/2 + qMax(us.width() + PADDING, es.width()/2),
 	  SCALE_HEIGHT + PADDING + ss.height() + 2*fm.descent());
 }
@@ -110,6 +108,7 @@ void ScaleItem::setLatitude(qreal lat)
 {
 	_lat = lat;
 	computeScale();
+	updateBoundingRect();
 	prepareGeometryChange();
 }
 
@@ -117,6 +116,7 @@ void ScaleItem::setZoom(int z)
 {
 	_zoom = z;
 	computeScale();
+	updateBoundingRect();
 	prepareGeometryChange();
 }
 
@@ -124,5 +124,6 @@ void ScaleItem::setUnits(enum Units units)
 {
 	_units = units;
 	computeScale();
+	updateBoundingRect();
 	prepareGeometryChange();
 }
diff --git a/src/scaleitem.h b/src/scaleitem.h
index 059e9f0e..895490a5 100644
--- a/src/scaleitem.h
+++ b/src/scaleitem.h
@@ -9,7 +9,7 @@ class ScaleItem : public QGraphicsItem
 public:
 	ScaleItem(QGraphicsItem *parent = 0);
 
-	QRectF boundingRect() const;
+	QRectF boundingRect() const {return _boundingRect;}
 	void paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
 	  QWidget *widget);
 
@@ -18,6 +18,7 @@ public:
 	void setUnits(enum Units units);
 
 private:
+	void updateBoundingRect();
 	void computeScale();
 	QString units() const;
 
@@ -27,6 +28,8 @@ private:
 	qreal _length;
 	Units _units;
 	bool _scale;
+
+	QRectF _boundingRect;
 };
 
 #endif // SCALEITEM_H
diff --git a/src/track.cpp b/src/track.cpp
index 044652d9..1613bc90 100644
--- a/src/track.cpp
+++ b/src/track.cpp
@@ -21,6 +21,9 @@ Track::Track(QWidget *parent)
 	setScene(_scene);
 	setCacheMode(QGraphicsView::CacheBackground);
 	setDragMode(QGraphicsView::ScrollHandDrag);
+#ifdef Q_OS_MAC
+	setViewportUpdateMode(QGraphicsView::FullViewportUpdate);
+#endif // Q_OS_MAC
 	setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
 	setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
 
@@ -388,7 +391,8 @@ void Track::paintEvent(QPaintEvent *e)
 {
 	QPointF scenePos = mapToScene(rect().bottomLeft() + QPoint(SCALE_OFFSET,
 	  -(SCALE_OFFSET + _mapScale->boundingRect().height())));
-	_mapScale->setPos(scenePos);
+	if (_mapScale->pos() != scenePos)
+		_mapScale->setPos(scenePos);
 
 	QGraphicsView::paintEvent(e);
 }