diff --git a/Polyhedron/demo/Polyhedron/Plugins/Mesh_3/Mesh_3_plugin.cpp b/Polyhedron/demo/Polyhedron/Plugins/Mesh_3/Mesh_3_plugin.cpp
index ac6af836d73..ff5569c35fb 100644
--- a/Polyhedron/demo/Polyhedron/Plugins/Mesh_3/Mesh_3_plugin.cpp
+++ b/Polyhedron/demo/Polyhedron/Plugins/Mesh_3/Mesh_3_plugin.cpp
@@ -265,14 +265,11 @@ void Mesh_3_plugin::mesh_3()
   ui.protect->setEnabled(features_protection_available);
   ui.protect->setChecked(features_protection_available);
 
+  ui.grayImgGroup->setVisible(image_item != NULL && image_item->isGray());
+
   // -----------------------------------
   // Get values
   // -----------------------------------
-  if(image_item && image_item->isGray())
-    ui.groupBox_3->setVisible(true);
-  else
-    ui.groupBox_3->setVisible(false);
-
   int i = dialog.exec();
   if( i == QDialog::Rejected ) { return; }
 
@@ -284,9 +281,9 @@ void Mesh_3_plugin::mesh_3()
   const double tet_sizing = !ui.noTetSizing->isChecked() ? 0  : ui.tetSizing->value();
   const bool protect_features = ui.protect->isChecked();
   const int manifold = ui.manifoldCheckBox->isChecked() ? 1 : 0;
-  const float iso_value = !ui.groupBox_3->isVisible() ? 0  : ui.iso_value_spinBox->value();
-  const float value_outside = !ui.groupBox_3->isVisible() ? 0  : ui.value_outside_spinBox->value();
-  const float inside_is_less = !ui.groupBox_3->isVisible() ? false  : ui.inside_is_less_checkBox->isChecked();
+  const float iso_value = !ui.grayImgGroup->isVisible() ? 0 : ui.iso_value_spinBox->value();
+  const float value_outside = !ui.grayImgGroup->isVisible() ? 0 : ui.value_outside_spinBox->value();
+  const float inside_is_less = !ui.grayImgGroup->isVisible() ? false : ui.inside_is_less_checkBox->isChecked();
 
   QApplication::setOverrideCursor(Qt::WaitCursor);
 
diff --git a/Polyhedron/demo/Polyhedron/Plugins/Mesh_3/Meshing_dialog.ui b/Polyhedron/demo/Polyhedron/Plugins/Mesh_3/Meshing_dialog.ui
index b4153c1e660..c3ee342b14c 100644
--- a/Polyhedron/demo/Polyhedron/Plugins/Mesh_3/Meshing_dialog.ui
+++ b/Polyhedron/demo/Polyhedron/Plugins/Mesh_3/Meshing_dialog.ui
@@ -344,7 +344,7 @@ p, li { white-space: pre-wrap; }
     </widget>
    </item>
    <item>
-    <widget class="QGroupBox" name="groupBox_3">
+    <widget class="QGroupBox" name="grayImgGroup">
      <property name="title">
       <string>Gray Images</string>
      </property>