wxGUI/timeline: draw grid behind data

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@73021 15284696-431f-4ddb-bdfa-cd5b030d7da7

gui/wxpython/timeline/frame.py

@@ -381,6 +381,7 @@ class TimelineFrame(wx.Frame):
         xlim = self.axes2d.get_xlim()
         padding = ceil((xlim[1] - xlim[0]) / 20.)
         self.axes2d.set_xlim(xlim[0] - padding, xlim[1] + padding)
+        self.axes2d.set_axisbelow(True)
 
         self.canvas.draw()
         DataCursor(plots, lookUp, InfoFormat)