refs #4932. Fix GCC error

Code/Mantid/Vates/ParaviewPlugins/ParaViewWidgets/QtWidgets/DimensionWidget.cpp

@@ -23,7 +23,7 @@ Constructor
 */
 DimensionWidget::DimensionWidget(Mantid::VATES::BinDisplay binDisplay)
 {
-  //TODO: The following cascade can be refactored out.
+  //Prefer dependency injection to the following conditional statements.
   if(binDisplay == Mantid::VATES::Simple)
   {
     m_binWidget = new SimpleBinInputWidget;

Code/Mantid/Vates/ParaviewPlugins/ParaViewWidgets/QtWidgets/LowHighStepInputWidget.cpp

@@ -37,8 +37,7 @@ LowHighStepInputWidget::LowHighStepInputWidget()
 
   connect(m_step, SIGNAL(editingFinished()), this, SLOT(nBinsListener()));
 
-  QDoubleValidator* stepValidator = new QDoubleValidator;
-  stepValidator->setBottom(0);
+  QDoubleValidator* stepValidator = new QDoubleValidator(0, 10000, 5, this);
   m_step->setValidator(stepValidator);
 
   QHBoxLayout* layout = new QHBoxLayout;