FIX: remove unnecessary code for removing artists

Author: dmgav

pyxrf/model/lineplot.py

@@ -1500,10 +1500,10 @@ def _show_preview_spectrum_plot(self):
         self.prepare_preview_spectrum_plot()
 
         # Remove all lines from the plot. This is not really needed, since the axes are cleared.
-        while len(self._lines_preview):
-            _ = self._lines_preview.pop()
-            if _.axes is not None:
-                _.remove()
+        # while len(self._lines_preview):
+        #     _ = self._lines_preview.pop()
+        #     if _.axes is not None:
+        #         _.remove()
 
         # The list of color names
         color_names = get_color_name()