Re #11422 Enable "n=" GUI element when power scale type selected

Code/Mantid/MantidPlot/src/ScaleDetails.cpp

@@ -403,6 +403,7 @@ void ScaleDetails::initWidgets()
     m_spnMajorValue->setValue(lst.count());
 
     checkstep();
+    checkscaletype();
 
     connect(m_grpAxesBreaks,SIGNAL(clicked()), this, SLOT(setModified()));
     connect(m_chkInvert,SIGNAL(clicked()), this, SLOT(setModified()));
@@ -415,8 +416,10 @@ void ScaleDetails::initWidgets()
     connect(m_cmbMinorValue,SIGNAL(currentIndexChanged(int)), this, SLOT(setModified()));
     connect(m_cmbUnit,SIGNAL(currentIndexChanged(int)), this, SLOT(setModified()));
     connect(m_cmbScaleType,SIGNAL(currentIndexChanged(int)), this, SLOT(setModified()));
+    connect(m_cmbScaleType,SIGNAL(currentIndexChanged(int)), this, SLOT(checkscaletype()));
     connect(m_dspnEnd, SIGNAL(valueChanged(double)), this, SLOT(setModified()));
     connect(m_dspnStart, SIGNAL(valueChanged(double)), this, SLOT(setModified()));
+    connect(m_dspnN, SIGNAL(valueChanged(double)), this, SLOT(setModified()));
     connect(m_dspnStep, SIGNAL(valueChanged(double)), this, SLOT(setModified()));
     connect(m_dspnBreakStart, SIGNAL(valueChanged(double)), this, SLOT(setModified()));
     connect(m_dspnStepBeforeBreak, SIGNAL(valueChanged(double)), this, SLOT(setModified()));
@@ -632,6 +635,22 @@ void ScaleDetails::checkstep()
   }
 }
 
+/*
+ * Enable the "n =" widget if X^n scale type is selected
+ */
+void ScaleDetails::checkscaletype()
+{
+  // If "power X^n" scale option is selected
+  if (m_cmbScaleType->currentIndex() == 2)
+  {
+    m_dspnN->setEnabled(true);
+  }
+  else
+  {
+    m_dspnN->setEnabled(false);
+  }
+}
+
 /**
  * Recalculates the minimum value allowed in step to stop too many labels being rendered
  */

Code/Mantid/MantidPlot/src/ScaleDetails.h

@@ -67,6 +67,7 @@ private slots:
   void radiosSwitched();
   void setModified();
   void recalcStepMin();
+  void checkscaletype();
 
 private:
   bool m_modified, m_initialised;