diff --git a/src/qgsdlgvectorlayerproperties.cpp b/src/qgsdlgvectorlayerproperties.cpp
index 05a3209e74b..c71828320fa 100644
--- a/src/qgsdlgvectorlayerproperties.cpp
+++ b/src/qgsdlgvectorlayerproperties.cpp
@@ -71,8 +71,7 @@ bufferRenderer(layer->
   txtDisplayName->setText(layer->name());
   // display type and feature count
   lblGeometryType->setText(QGis::qgisVectorGeometryType[layer->vectorType()]);
-  //QgsVectorDataProvider *dp = dynamic_cast<QgsVectorDataProvider *>(layer->getDataProvider());
-  QgsVectorDataProvider *dp = (QgsVectorDataProvider *)(layer->getDataProvider());
+  QgsVectorDataProvider *dp = dynamic_cast<QgsVectorDataProvider *>(layer->getDataProvider());
   QString numFeatures;
   numFeatures = numFeatures.setNum(dp->featureCount());
   lblFeatureCount->setText(numFeatures);
diff --git a/src/qgsgrasydialog.cpp b/src/qgsgrasydialog.cpp
index 7ac3a87b244..b97e71c5b4b 100644
--- a/src/qgsgrasydialog.cpp
+++ b/src/qgsgrasydialog.cpp
@@ -46,11 +46,7 @@ QgsGraSyDialog::QgsGraSyDialog(QgsVectorLayer * layer):QgsGraSyDialogBase(), mVe
 
     //find out the numerical fields of mVectorLayer
     QgsVectorDataProvider *provider;
-#ifndef WIN32
     if (provider = dynamic_cast<QgsVectorDataProvider *>(mVectorLayer->getDataProvider()))
-#else
-    if (provider = (QgsVectorDataProvider *)(mVectorLayer->getDataProvider()))
-#endif
     {
 	std::vector < QgsField > &fields = provider->fields();
 	int fieldnumber = 0;
@@ -84,19 +80,11 @@ QgsGraSyDialog::QgsGraSyDialog(QgsVectorLayer * layer):QgsGraSyDialogBase(), mVe
     //initial settings, use the buffer of the propertiesDialog if possible. If this is not possible, use the renderer of the vectorlayer directly
     if (mVectorLayer->propertiesDialog())
     {
-#ifndef WIN32
 	renderer = dynamic_cast < QgsGraduatedSymRenderer * >(layer->propertiesDialog()->getBufferRenderer());
-#else
-	renderer = (QgsGraduatedSymRenderer *)(layer->propertiesDialog()->getBufferRenderer());
-#endif
     } 
     else
     {
-#ifndef WIN32
 	renderer = dynamic_cast < QgsGraduatedSymRenderer * >(layer->renderer());
-#else
-	renderer = (QgsGraduatedSymRenderer *)(layer->renderer());
-#endif
     }
 
 
@@ -231,11 +219,7 @@ void QgsGraSyDialog::apply()
 	p.drawText(leftspace, topspace + fm.height(), name);
 	p.drawText(leftspace, topspace + 2 * fm.height(), classificationComboBox->currentText());
 	
-#ifndef WIN32	
 	QgsGraduatedSymRenderer *renderer = dynamic_cast < QgsGraduatedSymRenderer * >(mVectorLayer->renderer());
-#else
-	QgsGraduatedSymRenderer *renderer = (QgsGraduatedSymRenderer * )(mVectorLayer->renderer());
-#endif
 	
 	if (!renderer)
         {
@@ -342,11 +326,7 @@ void QgsGraSyDialog::adjustClassification()
 {
     mClassBreakBox->clear();
     QGis::VectorType m_type = mVectorLayer->vectorType();
-#ifndef WIN32
     QgsVectorDataProvider *provider = dynamic_cast<QgsVectorDataProvider *>(mVectorLayer->getDataProvider());
-#else
-    QgsVectorDataProvider *provider = (QgsVectorDataProvider *)(mVectorLayer->getDataProvider());
-#endif
     double minimum, maximum;
     
     //delete all previous entries
diff --git a/src/qgsrenderitem.cpp b/src/qgsrenderitem.cpp
index e9507cabdb2..39bd3c89c83 100644
--- a/src/qgsrenderitem.cpp
+++ b/src/qgsrenderitem.cpp
@@ -16,6 +16,7 @@
  ***************************************************************************/
 /* $Id$ */
 #include <qstring.h>
+#include <cassert>
 #include "qgsrenderitem.h"
 
 QgsRenderItem::QgsRenderItem(): mSymbol(new QgsSymbol())
@@ -59,7 +60,7 @@ void QgsRenderItem::setValue(QString value)
 }
 QgsSymbol* QgsRenderItem::getSymbol()
 {
-  Q_ASSERT(this == 0);
+  assert(this != 0);
     return mSymbol;
 }
 
diff --git a/src/qgssisydialog.cpp b/src/qgssisydialog.cpp
index ce4b0a31437..7e2f06b5910 100644
--- a/src/qgssisydialog.cpp
+++ b/src/qgssisydialog.cpp
@@ -52,19 +52,11 @@ QgsSiSyDialog::QgsSiSyDialog(QgsVectorLayer * layer):QgsSiSyDialogBase(), mVecto
 	//initial settings, use the buffer of the propertiesDialog if possible. If this is not possible, use the renderer of the vectorlayer directly
 	if (mVectorLayer->propertiesDialog())
         {
-#ifdef WIN32
 	    renderer = dynamic_cast < QgsSingleSymRenderer * >(layer->propertiesDialog()->getBufferRenderer());
-#else
-	    renderer = (QgsSingleSymRenderer * )(layer->propertiesDialog()->getBufferRenderer());
-#endif
 	} 
 	else
         {
-#ifdef WIN32
 	    renderer = dynamic_cast < QgsSingleSymRenderer * >(layer->renderer());
-#else
-	    renderer = (QgsSingleSymRenderer *)(layer->renderer());
-#endif
         }
 
   if (renderer)
diff --git a/src/qgsuvaldialog.cpp b/src/qgsuvaldialog.cpp
index 05b75093aec..2135911123f 100644
--- a/src/qgsuvaldialog.cpp
+++ b/src/qgsuvaldialog.cpp
@@ -38,11 +38,7 @@ QgsUValDialog::QgsUValDialog(QgsVectorLayer* vl): QgsUValDialogBase(), mVectorLa
 
     //find out the fields of mVectorLayer
     QgsVectorDataProvider *provider;
-#ifndef WIN32
     if (provider = dynamic_cast<QgsVectorDataProvider *>(mVectorLayer->getDataProvider()))
-#else
-    if (provider = (QgsVectorDataProvider *)(mVectorLayer->getDataProvider()))
-#endif
     {
 	std::vector < QgsField > &fields = provider->fields();
 	QString str;
@@ -71,19 +67,11 @@ QgsUValDialog::QgsUValDialog(QgsVectorLayer* vl): QgsUValDialogBase(), mVectorLa
     //initial settings, use the buffer of the propertiesDialog if possible. If this is not possible, use the renderer of the vectorlayer directly
     if (mVectorLayer->propertiesDialog())
     {
-#ifndef WIN32
 	renderer = dynamic_cast < QgsUniqueValRenderer * >(mVectorLayer->propertiesDialog()->getBufferRenderer());
-#else
-	renderer = (QgsUniqueValRenderer * )(mVectorLayer->propertiesDialog()->getBufferRenderer());
-#endif
     } 
     else
     {
-#ifndef WIN32
 	renderer = dynamic_cast < QgsUniqueValRenderer * >(mVectorLayer->renderer());
-#else
-	renderer = ( QgsUniqueValRenderer * )(mVectorLayer->renderer());
-#endif
     }
 
 
@@ -151,11 +139,7 @@ void QgsUValDialog::apply()
 	}
     }
 
-#ifndef WIN32
     QgsUniqueValRenderer *renderer = dynamic_cast < QgsUniqueValRenderer * >(mVectorLayer->renderer());
-#else
-    QgsUniqueValRenderer *renderer = ( QgsUniqueValRenderer * )(mVectorLayer->renderer());
-#endif
 
     //go through mValues and add the entries to the renderer
     if(renderer)
@@ -276,11 +260,7 @@ void QgsUValDialog::changeClassificationAttribute(int nr)
     }
     mValues.clear();
     
-#ifndef WIN32
     QgsVectorDataProvider *provider = dynamic_cast<QgsVectorDataProvider *>(mVectorLayer->getDataProvider());
-#else
-    QgsVectorDataProvider *provider = (QgsVectorDataProvider *)(mVectorLayer->getDataProvider());
-#endif
     if (provider)
     {
 	QString value;