From 8f3b86f2e990fe9ae08bd64833438ac3a56ff136 Mon Sep 17 00:00:00 2001
From: Alexander Bruy <alexander.bruy@gmail.com>
Date: Sun, 23 Jun 2019 14:20:12 +0300
Subject: [PATCH] update number of classes in the graduated renderer after
 adding new classes with the histogram (fix #29796)

---
 src/gui/symbology/qgsgraduatedsymbolrendererwidget.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/gui/symbology/qgsgraduatedsymbolrendererwidget.cpp b/src/gui/symbology/qgsgraduatedsymbolrendererwidget.cpp
index 5c40bddc46d..0dfe1ab5e1e 100644
--- a/src/gui/symbology/qgsgraduatedsymbolrendererwidget.cpp
+++ b/src/gui/symbology/qgsgraduatedsymbolrendererwidget.cpp
@@ -818,6 +818,11 @@ void QgsGraduatedSymbolRendererWidget::refreshRanges( bool reset )
     return;
 
   mModel->updateSymbology( reset );
+
+  disconnectUpdateHandlers();
+  spinGraduatedClasses->setValue( mRenderer->ranges().count() );
+  connectUpdateHandlers();
+
   emit widgetChanged();
 }