diff --git a/src/shadereffectitem.cpp b/src/shadereffectitem.cpp
index dbfe2a9..9dc864d 100644
--- a/src/shadereffectitem.cpp
+++ b/src/shadereffectitem.cpp
@@ -201,6 +201,7 @@ Rectangle {
 
 ShaderEffectItem::ShaderEffectItem(QDeclarativeItem *parent)
     : QDeclarativeItem(parent)
+    , m_program(0)
     , m_meshResolution(1, 1)
     , m_geometry(QSGGeometry::defaultAttributes_TexturedPoint2D(), 4)
     , m_blending(true)
@@ -214,10 +215,18 @@ ShaderEffectItem::ShaderEffectItem(QDeclarativeItem *parent)
     , m_hasShaderPrograms(false)
     , m_mirrored(false)
     , m_defaultVertexShader(true)
+    , m_lastContext(0)
 {
     setFlag(QGraphicsItem::ItemHasNoContents, false);
     connect(this, SIGNAL(visibleChanged()), this, SLOT(handleVisibilityChange()));
     m_active = isVisible();
+
+    // In Symbian OS QGLShaderProgram is not created here, but instead it is created
+    // later to minimize GPU memory usage.
+#ifndef Q_OS_SYMBIAN
+    m_program = new QGLShaderProgram(this);
+    m_lastContext = const_cast <QGLContext*> (QGLContext::currentContext());
+#endif
 }
 
 ShaderEffectItem::~ShaderEffectItem()
@@ -426,10 +435,24 @@ void ShaderEffectItem::renderEffect(QPainter *painter, const QMatrix4x4 &matrix)
     if (!painter || !painter->device())
         return;
 
-    if (!m_program.isLinked() || m_program_dirty)
+    QGLContext *context = const_cast <QGLContext*> (QGLContext::currentContext());
+    if (!m_program || !m_lastContext || !QGLContext::areSharing(context, m_lastContext)) {
+        // Context has changed, re-create QGLShaderProgram
+        if (context) {
+            delete m_program;
+            m_program = 0;
+            m_program = new QGLShaderProgram(this);
+            m_lastContext = context;
+        }
+    }
+
+    if (!m_program)
+        return;
+
+    if (!m_program->isLinked() || m_program_dirty)
         updateShaderProgram();
 
-    m_program.bind();
+    m_program->bind();
 
     QMatrix4x4 combinedMatrix;
     combinedMatrix.scale(2.0 / painter->device()->width(), -2.0 / painter->device()->height(), 1.0);
@@ -438,7 +461,7 @@ void ShaderEffectItem::renderEffect(QPainter *painter, const QMatrix4x4 &matrix)
     updateEffectState(combinedMatrix);
 
     for (int i = 0; i < m_attributeNames.size(); ++i) {
-        m_program.enableAttributeArray(m_geometry.attributes()[i].position);
+        m_program->enableAttributeArray(m_geometry.attributes()[i].position);
     }
 
     bindGeometry();
@@ -476,11 +499,14 @@ void ShaderEffectItem::renderEffect(QPainter *painter, const QMatrix4x4 &matrix)
     glDisable(GL_DEPTH_TEST);
 
    for (int i = 0; i < m_attributeNames.size(); ++i)
-        m_program.disableAttributeArray(m_geometry.attributes()[i].position);
+        m_program->disableAttributeArray(m_geometry.attributes()[i].position);
 }
 
 void ShaderEffectItem::updateEffectState(const QMatrix4x4 &matrix)
 {
+    if (!m_program)
+        return;
+
     for (int i = m_sources.size() - 1; i >= 0; --i) {
         const ShaderEffectItem::SourceData &source = m_sources.at(i);
         if (!source.source)
@@ -491,10 +517,10 @@ void ShaderEffectItem::updateEffectState(const QMatrix4x4 &matrix)
     }
 
     if (m_respectsOpacity)
-        m_program.setUniformValue("qt_Opacity", static_cast<float> (effectiveOpacity()));
+        m_program->setUniformValue("qt_Opacity", static_cast<float> (effectiveOpacity()));
 
     if (m_respectsMatrix){
-        m_program.setUniformValue("qt_ModelViewProjectionMatrix", matrix);
+        m_program->setUniformValue("qt_ModelViewProjectionMatrix", matrix);
     }
 
     QSet<QByteArray>::const_iterator it;
@@ -504,37 +530,37 @@ void ShaderEffectItem::updateEffectState(const QMatrix4x4 &matrix)
 
         switch (v.type()) {
         case QVariant::Color:
-            m_program.setUniformValue(name.constData(), qvariant_cast<QColor>(v));
+            m_program->setUniformValue(name.constData(), qvariant_cast<QColor>(v));
             break;
         case QVariant::Double:
-            m_program.setUniformValue(name.constData(), (float) qvariant_cast<double>(v));
+            m_program->setUniformValue(name.constData(), (float) qvariant_cast<double>(v));
             break;
         case QVariant::Transform:
-            m_program.setUniformValue(name.constData(), qvariant_cast<QTransform>(v));
+            m_program->setUniformValue(name.constData(), qvariant_cast<QTransform>(v));
             break;
         case QVariant::Int:
-            m_program.setUniformValue(name.constData(), v.toInt());
+            m_program->setUniformValue(name.constData(), v.toInt());
             break;
         case QVariant::Bool:
-            m_program.setUniformValue(name.constData(), GLint(v.toBool()));
+            m_program->setUniformValue(name.constData(), GLint(v.toBool()));
             break;
         case QVariant::Size:
         case QVariant::SizeF:
-            m_program.setUniformValue(name.constData(), v.toSizeF());
+            m_program->setUniformValue(name.constData(), v.toSizeF());
             break;
         case QVariant::Point:
         case QVariant::PointF:
-            m_program.setUniformValue(name.constData(), v.toPointF());
+            m_program->setUniformValue(name.constData(), v.toPointF());
             break;
         case QVariant::Rect:
         case QVariant::RectF:
         {
             QRectF r = v.toRectF();
-            m_program.setUniformValue(name.constData(), r.x(), r.y(), r.width(), r.height());
+            m_program->setUniformValue(name.constData(), r.x(), r.y(), r.width(), r.height());
         }
             break;
         case QVariant::Vector3D:
-            m_program.setUniformValue(name.constData(), qvariant_cast<QVector3D>(v));
+            m_program->setUniformValue(name.constData(), qvariant_cast<QVector3D>(v));
             break;
         default:
             break;
@@ -562,6 +588,9 @@ static inline int size_of_type(GLenum type)
 
 void ShaderEffectItem::bindGeometry()
 {
+    if (!m_program)
+        return;
+
     char const *const *attrNames = m_attributeNames.constData();
     int offset = 0;
         for (int j = 0; j < m_attributeNames.size(); ++j) {
@@ -578,7 +607,7 @@ void ShaderEffectItem::bindGeometry()
         if (normalize)
             qWarning() << "ShaderEffectItem::bindGeometry() - non supported attribute type!";
 
-        m_program.setAttributeArray(a.position, (GLfloat*) (((char*) m_geometry.vertexData()) + offset), a.tupleSize, m_geometry.stride());
+        m_program->setAttributeArray(a.position, (GLfloat*) (((char*) m_geometry.vertexData()) + offset), a.tupleSize, m_geometry.stride());
         //glVertexAttribPointer(a.position, a.tupleSize, a.type, normalize, m_geometry.stride(), (char *) m_geometry.vertexData() + offset);
         offset += a.tupleSize * size_of_type(a.type);
     }
@@ -661,6 +690,15 @@ void ShaderEffectItem::setActive(bool enable)
         }
     }
 
+    // In Symbian OS QGLShaderProgram is deleted when not active (to minimize GPU memory usage).
+#ifdef Q_OS_SYMBIAN
+    if (!m_active && m_program) {
+        delete m_program;
+        m_program = 0;
+        m_lastContext = 0;
+    }
+#endif
+
     emit activeChanged();
     markDirty();
 }
@@ -780,7 +818,9 @@ void ShaderEffectItem::reset()
 {
     disconnectPropertySignals();
 
-    m_program.removeAllShaders();
+    if (m_program)
+        m_program->removeAllShaders();
+
     m_attributeNames.clear();
     m_uniformNames.clear();
     for (int i = 0; i < m_sources.size(); ++i) {
@@ -825,6 +865,9 @@ void ShaderEffectItem::updateProperties()
 
 void ShaderEffectItem::updateShaderProgram()
 {
+    if (!m_program)
+        return;
+
     QString vertexCode = m_vertex_code;
     QString fragmentCode = m_fragment_code;
 
@@ -834,16 +877,16 @@ void ShaderEffectItem::updateShaderProgram()
     if (fragmentCode.isEmpty())
         fragmentCode = QString::fromLatin1(qt_default_fragment_code);
 
-    m_program.addShaderFromSourceCode(QGLShader::Vertex, vertexCode);
-    m_program.addShaderFromSourceCode(QGLShader::Fragment, fragmentCode);
+    m_program->addShaderFromSourceCode(QGLShader::Vertex, vertexCode);
+    m_program->addShaderFromSourceCode(QGLShader::Fragment, fragmentCode);
 
     for (int i = 0; i < m_attributeNames.size(); ++i) {
-        m_program.bindAttributeLocation(m_attributeNames.at(i), m_geometry.attributes()[i].position);
+        m_program->bindAttributeLocation(m_attributeNames.at(i), m_geometry.attributes()[i].position);
     }
 
-    if (!m_program.link()) {
+    if (!m_program->link()) {
         qWarning("ShaderEffectItem: Shader compilation failed:");
-        qWarning() << m_program.log();
+        qWarning() << m_program->log();
     }
 
     if (!m_attributeNames.contains(qt_postion_attribute_name))
@@ -853,10 +896,10 @@ void ShaderEffectItem::updateShaderProgram()
     if (!m_respectsMatrix)
         qWarning("ShaderEffectItem: Missing reference to \'qt_ModelViewProjectionMatrix\'.");
 
-    if (m_program.isLinked()) {
-        m_program.bind();
+    if (m_program->isLinked()) {
+        m_program->bind();
         for (int i = 0; i < m_sources.size(); ++i)
-            m_program.setUniformValue(m_sources.at(i).name.constData(), i);
+            m_program->setUniformValue(m_sources.at(i).name.constData(), i);
     }
 
     m_program_dirty = false;
diff --git a/src/shadereffectitem.h b/src/shadereffectitem.h
index 1d27543..7b70228 100644
--- a/src/shadereffectitem.h
+++ b/src/shadereffectitem.h
@@ -115,7 +115,7 @@ private:
 private:
     QString m_fragment_code;
     QString m_vertex_code;
-    QGLShaderProgram m_program;
+    QGLShaderProgram* m_program;
     QVector<const char *> m_attributeNames;
     QSet<QByteArray> m_uniformNames;
     QSize m_meshResolution;
@@ -143,6 +143,8 @@ private:
     bool m_hasShaderPrograms : 1;
     bool m_mirrored : 1;
     bool m_defaultVertexShader : 1;
+
+    QGLContext* m_lastContext;
 };
 
 QT_END_HEADER
diff --git a/src/shadereffectsource.cpp b/src/shadereffectsource.cpp
index dec3bb0..2c25f2f 100644
--- a/src/shadereffectsource.cpp
+++ b/src/shadereffectsource.cpp
@@ -170,15 +170,11 @@ void ShaderEffectSource::setSourceRect(const QRectF &rect)
         return;
     m_sourceRect = rect;
     updateSizeAndTexture();
-    updateBackbuffer();
     emit sourceRectChanged();
     emit repaintRequired();
 
-    if (m_sourceItem) {
-        ShaderEffect* effect = qobject_cast<ShaderEffect*> (m_sourceItem->graphicsEffect());
-        if (effect)
-            effect->m_changed = true;
-    }
+    m_dirtyTexture = true;
+    markSourceItemDirty();
 }
 
 /*!
@@ -207,11 +203,8 @@ void ShaderEffectSource::setTextureSize(const QSize &size)
     emit textureSizeChanged();
     emit repaintRequired();
 
-    if (m_sourceItem) {
-        ShaderEffect* effect = qobject_cast<ShaderEffect*> (m_sourceItem->graphicsEffect());
-        if (effect)
-            effect->m_changed = true;
-    }
+    m_dirtyTexture = true;
+    markSourceItemDirty();
 }
 
 /*!
@@ -294,8 +287,10 @@ void ShaderEffectSource::setWrapMode(WrapMode mode)
         return;
 
     m_wrapMode = mode;
-    updateBackbuffer();
     emit wrapModeChanged();
+
+    m_dirtyTexture = true;
+    markSourceItemDirty();
 }
 
 /*!
@@ -314,7 +309,7 @@ void ShaderEffectSource::grab()
     emit repaintRequired();
 }
 
-void ShaderEffectSource::bind() const
+void ShaderEffectSource::bind()
 {
     GLint filtering = smooth() ? GL_LINEAR : GL_NEAREST;
     GLuint hwrap = (m_wrapMode == Repeat || m_wrapMode == RepeatHorizontally) ? GL_REPEAT : GL_CLAMP_TO_EDGE;
@@ -323,9 +318,13 @@ void ShaderEffectSource::bind() const
 #if !defined(QT_OPENGL_ES_2)
     glEnable(GL_TEXTURE_2D);
 #endif
-    if (m_fbo) {
+
+    if (m_fbo && m_fbo->isValid()) {
         glBindTexture(GL_TEXTURE_2D, m_fbo->texture());
     } else {
+        m_dirtyTexture = true;
+        emit repaintRequired();
+        markSourceItemDirty();
         glBindTexture(GL_TEXTURE_2D, 0);
     }
 
@@ -354,7 +353,7 @@ void ShaderEffectSource::derefFromEffectItem()
 
 void ShaderEffectSource::updateBackbuffer()
 {
-    if (!m_sourceItem)
+    if (!m_sourceItem || !QGLContext::currentContext())
         return;
 
     // Multisampling is not (for now) supported.
@@ -370,7 +369,7 @@ void ShaderEffectSource::updateBackbuffer()
         if (!m_fbo) {
             m_fbo =  new ShaderEffectBuffer(size, format);
         } else {
-            if (m_fbo->size() != size || m_fbo->format().internalTextureFormat() != GLenum(m_format)) {
+            if (!m_fbo->isValid() || m_fbo->size() != size || m_fbo->format().internalTextureFormat() != GLenum(m_format)) {
                 delete m_fbo;
                 m_fbo = 0;
                 m_fbo =  new ShaderEffectBuffer(size, format);
@@ -397,6 +396,16 @@ void ShaderEffectSource::markSourceSizeDirty()
         emit repaintRequired();
 }
 
+void ShaderEffectSource::markSourceItemDirty()
+{
+    m_dirtyTexture = true;
+    if (m_sourceItem) {
+        ShaderEffect* effect = qobject_cast<ShaderEffect*> (m_sourceItem->graphicsEffect());
+        if (effect)
+            effect->m_changed = true;
+    }
+}
+
 void ShaderEffectSource::updateSizeAndTexture()
 {
     if (m_sourceItem) {
@@ -407,7 +416,7 @@ void ShaderEffectSource::updateSizeAndTexture()
             size.setWidth(1);
         if (size.height() < 1)
             size.setHeight(1);
-        if (m_fbo && m_fbo->size() != size) {
+        if (m_fbo && (m_fbo->size() != size || !m_fbo->isValid())) {
             delete m_fbo;
             m_fbo = 0;
             delete m_multisampledFbo;
diff --git a/src/shadereffectsource.h b/src/shadereffectsource.h
index 275e5b2..9c69548 100644
--- a/src/shadereffectsource.h
+++ b/src/shadereffectsource.h
@@ -99,7 +99,7 @@ public:
     void setWrapMode(WrapMode mode);
 
     bool isActive() const { return m_refs; }
-    void bind() const;
+    void bind();
     void refFromEffectItem();
     void derefFromEffectItem();
     void updateBackbuffer();
@@ -124,6 +124,7 @@ Q_SIGNALS:
 public Q_SLOTS:
     void markSceneGraphDirty();
     void markSourceSizeDirty();
+    void markSourceItemDirty();
 
 private:
     void updateSizeAndTexture();
diff --git a/tests/manual/qmlshadersplugintest/qml/qmlshadersplugintest/TestHideOriginal.qml b/tests/manual/qmlshadersplugintest/qml/qmlshadersplugintest/TestHideOriginal.qml
index 1cd449f..fc7ddb0 100644
--- a/tests/manual/qmlshadersplugintest/qml/qmlshadersplugintest/TestHideOriginal.qml
+++ b/tests/manual/qmlshadersplugintest/qml/qmlshadersplugintest/TestHideOriginal.qml
@@ -75,7 +75,8 @@ Rectangle {
         varying highp vec2 qt_TexCoord0;
         uniform sampler2D source;
         void main() {
-            // Empty fragmentshader, we do not write any pixels via this effect item. We only observe hideoriginal functionality.
+            gl_FragColor = vec4(0.0, 0.0, 0.0, 0.0);
+            // We do not write any visible pixels via this effect item. We only observe hideoriginal functionality.
         }
         "
     }