Fix bug where twin axes drawn twice

Author: lukelbd

CHANGELOG.rst

@@ -15,14 +15,20 @@ ProPlot v1.0.0 (2020-##-##)
 This will be published when some major refactoring tasks are completed.
 See :pr:`45`, :pr:`46`, and :pr:`50`.
 
+ProPlot v0.2.6 (2019-12-XX)
+===========================
+Bug fixes
+---------
+- Fix issue where twin axes are drawn *twice*.
+
+
 ProPlot v0.2.5 (2019-12-07)
 ===========================
 Features
 --------
 - Much better `~proplot.axistools.CutoffScale` algorithm, permit arbitrary
   cutoffs (:pr:`83`).
 
-
 ProPlot v0.2.4 (2019-12-07)
 ===========================
 Deprecated

proplot/axes.py

@@ -2561,6 +2561,7 @@ def altx(self, *args, **kwargs):
         self._altx_overrides()
         ax._altx_overrides()
         self.add_child_axes(ax)
+        self.figure._axstack.remove(ax)  # or gets drawn twice!
         return ax
 
     def alty(self):
@@ -2578,6 +2579,7 @@ def alty(self):
         self._alty_overrides()
         ax._alty_overrides()
         self.add_child_axes(ax)
+        self.figure._axstack.remove(ax)  # or gets drawn twice!
         return ax
 
     def dualx(self, transform, transform_kw=None, **kwargs):