              The scale widget
          """
          logger.debug("Adding scale slider")
          self.slider_var.set(100)
          slider = tk.Scale(self,
                            orient=tk.HORIZONTAL,
                            to=self.max_scale,
                            showvalue=False,
                            variable=self.slider_var,
                            command=self._on_slider_update)
 
</s> remove         scale = ttk.Combobox(self,
 </s> add         scale = ttk.Combobox(self._frame, </s> remove         self.pack(side=tk.BOTTOM, fill=tk.X, padx=2, pady=2)
 </s> add             self._frame.pack(side=tk.BOTTOM, fill=tk.X, padx=2, pady=2)

        slider = tk.Scale(self._frame,
              The scale widget
          """
          logger.debug("Adding scale slider")
          self.slider_var.set(100)
        slider = tk.Scale(self._frame,
                            orient=tk.HORIZONTAL,
                            to=self.max_scale,
                            showvalue=False,
                            variable=self.slider_var,
                            command=self._on_slider_update)
keep keep keep keep replace keep keep keep keep keep
 GUI - Preview updates
  - Training preview. Embed preview pop-out window
  - Bugfix - convert/extract previews 
lib/training/preview_tk.py