diff --git a/schainpy/Graphics/SpectraPlot.py b/schainpy/Graphics/SpectraPlot.py
index a071e09..0eff6ff 100644
--- a/schainpy/Graphics/SpectraPlot.py
+++ b/schainpy/Graphics/SpectraPlot.py
@@ -124,6 +124,8 @@ class Spectrum():
         if not(self.__isPlotIni):
             self.iniPlot()
         
+        plplot.plsstrm(self.indexPlot)
+        
         data = 10.*numpy.log10(self.m_Spectra.data_spc)
         
         nX, nY, nChan = numpy.shape(data)
diff --git a/schainpy/Graphics/VoltagePlot.py b/schainpy/Graphics/VoltagePlot.py
index 6cd4619..648cda4 100644
--- a/schainpy/Graphics/VoltagePlot.py
+++ b/schainpy/Graphics/VoltagePlot.py
@@ -105,6 +105,8 @@ class Osciloscope():
         if not(self.__isPlotIni):
             self.iniPlot()
         
+        plplot.plsstrm(self.indexPlot)
+        
         data = self.m_Voltage.data
               
         x = self.m_Voltage.heights