IntensityDataProjectionsWidget: fix switching between data in projection mode

GUI/View/Projection/IntensityDataProjectionsWidget.cpp

@@ -79,6 +79,11 @@ void IntensityDataProjectionsWidget::setContext()
     m_selectionModel.reset(new QItemSelectionModel(containerModel));
 
     m_projectionsCanvas->setSelectionModel(m_selectionModel.get());
+
+    // The following line must come before 'm_projectionsCanvas->setContext()'!
+    // It prevents problem with switching between datasets in projectoin mode.
+    m_projectionsWidget->disconnectItem();
+
     m_projectionsCanvas->setContext(currentIntensityDataItem());
     m_projectionsWidget->setIntensityItem(currentIntensityDataItem());