From 4c51956b896264366b8e422542e25bac8e5c8ba1 Mon Sep 17 00:00:00 2001
From: Leyan <ouyang.leyan@hotmail.com>
Date: Sun, 24 Aug 2014 23:14:17 +0800
Subject: [PATCH] use previous renderer if possible, instead of last applied
 renderer

---
 .../symbology-ng/qgsrendererv2propertiesdialog.cpp  | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/gui/symbology-ng/qgsrendererv2propertiesdialog.cpp b/src/gui/symbology-ng/qgsrendererv2propertiesdialog.cpp
index bed3c58b31f7..3889a769936e 100644
--- a/src/gui/symbology-ng/qgsrendererv2propertiesdialog.cpp
+++ b/src/gui/symbology-ng/qgsrendererv2propertiesdialog.cpp
@@ -144,6 +144,17 @@ void QgsRendererV2PropertiesDialog::rendererChanged()
 
   QString rendererName = cboRenderers->itemData( cboRenderers->currentIndex() ).toString();
 
+  //Retrieve the previous renderer: from the old active widget if possible, otherwise from the layer
+  QgsFeatureRendererV2* oldRenderer;
+  if ( mActiveWidget )
+  {
+    oldRenderer = mActiveWidget->renderer()->clone();
+  }
+  else
+  {
+    oldRenderer = mLayer->rendererV2()->clone();
+  }
+
   // get rid of old active widget (if any)
   if ( mActiveWidget )
   {
@@ -156,7 +167,7 @@ void QgsRendererV2PropertiesDialog::rendererChanged()
   QgsRendererV2Widget* w = NULL;
   QgsRendererV2AbstractMetadata* m = QgsRendererV2Registry::instance()->rendererMetadata( rendererName );
   if ( m != NULL )
-    w = m->createRendererWidget( mLayer, mStyle, mLayer->rendererV2()->clone() );
+    w = m->createRendererWidget( mLayer, mStyle, oldRenderer );
 
   if ( w != NULL )
   {