Set None be the default for box plot zorder

Author: bcongdon

lib/matplotlib/axes/_axes.py

@@ -3095,7 +3095,7 @@ def boxplot(self, x, notch=None, sym=None, vert=None, whis=None,
                 showbox=None, showfliers=None, boxprops=None,
                 labels=None, flierprops=None, medianprops=None,
                 meanprops=None, capprops=None, whiskerprops=None,
-                manage_xticks=True, autorange=False, zorder=2):
+                manage_xticks=True, autorange=False, zorder=None):
         """
         Make a box and whisker plot.
 
@@ -3108,7 +3108,7 @@ def boxplot(self, x, notch=None, sym=None, vert=None, whis=None,
                   showbox=True, showfliers=True, boxprops=None,
                   labels=None, flierprops=None, medianprops=None,
                   meanprops=None, capprops=None, whiskerprops=None,
-                  manage_xticks=True, autorange=False, zorder=2):
+                  manage_xticks=True, autorange=False, zorder=None):
 
         Make a box and whisker plot for each column of ``x`` or each
         vector in sequence ``x``.  The box extends from the lower to
@@ -3220,7 +3220,7 @@ def boxplot(self, x, notch=None, sym=None, vert=None, whis=None,
             ``shownotches`` is also True. Otherwise, means will be shown
             as points.
 
-        zorder : scalar, optional (2)
+        zorder : scalar, optional (None)
             Sets the zorder of the boxplot.
 
         Other Parameters
@@ -3401,7 +3401,7 @@ def bxp(self, bxpstats, positions=None, widths=None, vert=True,
             showcaps=True, showbox=True, showfliers=True,
             boxprops=None, whiskerprops=None, flierprops=None,
             medianprops=None, capprops=None, meanprops=None,
-            meanline=False, manage_xticks=True, zorder=2):
+            meanline=False, manage_xticks=True, zorder=None):
         """
         Drawing function for box and whisker plots.
 
@@ -3412,7 +3412,7 @@ def bxp(self, bxpstats, positions=None, widths=None, vert=True,
               showcaps=True, showbox=True, showfliers=True,
               boxprops=None, whiskerprops=None, flierprops=None,
               medianprops=None, capprops=None, meanprops=None,
-              meanline=False, manage_xticks=True, zorder=2):
+              meanline=False, manage_xticks=True, zorder=None):
 
         Make a box and whisker plot for each column of *x* or each
         vector in sequence *x*.  The box extends from the lower to
@@ -3516,7 +3516,7 @@ def bxp(self, bxpstats, positions=None, widths=None, vert=True,
         manage_xticks : bool, default = True
           If the function should adjust the xlim and xtick locations.
 
-        zorder : scalar,  default = 2
+        zorder : scalar,  default = None
           The zorder of the resulting boxplot
 
         Returns
@@ -3561,6 +3561,10 @@ def bxp(self, bxpstats, positions=None, widths=None, vert=True,
         # empty list of xticklabels
         datalabels = []
 
+        # Use default zorder if none specified
+        if zorder is None:
+            zorder = mlines.Line2D.zorder
+
         zdelta = 0.1
         # box properties
         if patch_artist: